This disclosure relates generally to Computer-Aided Design
(CAD), and more particularly to method and system for generating tightest
revolve envelope for a CAD Boundary representation (B-rep) model.
Background
[002] Solid modeling is a term that refers to a set of techniques
that may be used to create and store computer-based representations of
physical objects. Several techniques have evolved over the years for
providing computer-based representations of 3-dimensional (3D) parts. One
of these techniques is Boundary Representation (B-rep).
[003] A B-rep model of a mechanical part consists of a plurality of
faces, a plurality of edges and a plurality of vertices, which are connected
to form a topological structure of the mechanical part. By using such a
representation, it is possible to evaluate many properties of the mechanical
part from a computer model. B-rep based computer models may be cut and
examined in a manner like a real part. Turning is a form of machining, a
material removal process, which is used to create rotational, typically axisymmetric, parts by cutting away unwanted material. In turning, raw material
is a piece of stock. The stock is available in a variety of shapes such as solid
cylindrical bars and hollow tubes.
[004] A revolve envelope of a solid model is the rotational, axisymmetric region that encloses the solid model. Size of the revolve
envelope has a direct bearing on choice of stock size for turning operation.
Smaller the stock size, lower the material cost, production cost, and tooling
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cost. Therefore, it is imperative to compute tightest revolve envelope of a
solid model to minimize costs.
[005] The conventional technqiues fail to provide for methods to
optimally determine the tightest revolve envelope for a model. In the present
scenario, stock sizes are not optimized leading to wastage of stock material
and higher production costs. There is, therefore, a need in the present state
of art for techniques to determine tightest revolve envelopes corresponding
to B-rep solid models.
SUMMARY
[006] In one embodiment, a method for generating tightest revolve
envelope for a Boundary representation (B-rep) Computer-Aided Design
(CAD) model is disclosed. In one example, the method includes receiving a
2-dimensional (2D) point cloud within an XY-plane corresponding to each of
a plurality of faces of the B-rep CAD model within an XYZ-space. The 2D
point cloud includes a plurality of discrete 2D data points within the XYplane. The method further includes, for each of the plurality of faces of the
B-rep CAD model, determining a concave hull shape for the 2D point cloud
through a concave hull algorithm. The method further includes combining
the concave hull shape corresponding to each of the plurality of faces of the
B-rep CAD model through at least one of a Boolean operation and a
stitching operation to obtain a tightest revolve profile of the B-rep CAD
model. The method further includes revolving the tightest revolve profile
about X-axis of the XYZ-space to obtain a tightest revolve envelope
corresponding to the B-rep CAD model.
[007] In one embodiment, a system for generating tightest revolve
envelope for a B-rep CAD model is disclosed. In one example, the system
includes a processor and a computer-readable medium communicatively
coupled to the processor. The computer-readable medium store processorexecutable instructions, which, on execution, cause the processor to receive
a 2D point cloud within an XY-plane corresponding to each of a plurality of
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faces of the B-rep CAD model within an XYZ-space. The 2D point cloud
includes a plurality of discrete 2D data points within the XY-plane. The
processor-executable instructions, on execution, further cause the
processor to, for each of the plurality of faces of the B-rep CAD model,
determine a concave hull shape for the 2D point cloud through a concave
hull algorithm. The processor-executable instructions, on execution, further
cause the processor to combine the concave hull shape corresponding to
each of the plurality of faces of the B-rep CAD model through at least one
of a Boolean operation and a stitching operation to obtain a tightest revolve
profile of the B-rep CAD model. The processor-executable instructions, on
execution, further cause the processor to revolve the tightest revolve profile
about X-axis of the XYZ-space to obtain a tightest revolve envelope
corresponding to the B-rep CAD model.
[008] It is to be understood that both the foregoing general
description and the following detailed description are exemplary and
explanatory only and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[009] The accompanying drawings, which are incorporated in and
constitute a part of this disclosure, illustrate exemplary embodiments and,
together with the description, serve to explain the disclosed principles.
[010] FIG. 1 is a block diagram of an exemplary system for
generating tightest revolve envelope for a Boundary representation (B-rep)
Computer-Aided Design (CAD) model, in accordance with some
embodiments of the present disclosure.
[011] FIG. 2 illustrates a functional block diagram of an exemplary
system for generating tightest revolve envelope for a B-rep CAD model, in
accordance with some embodiments of the present disclosure.
[012] FIGS. 3A and 3B illustrate a flow diagram of an exemplary
process for generating tightest revolve envelope for a B-rep CAD model, in
accordance with some embodiments of the present disclosure.
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[013] FIGS. 4A and FIG. 4B illustrate a B-rep CAD model, tightest
revolve profile corresponding to the B-rep CAD model, and tightest revolve
envelope corresponding to the B-rep CAD model, in accordance with some
embodiments of the present disclosure.
[014] FIGS. 5A and 5B illustrate a B-rep CAD model with 3D point
cloud of a face in XYZ space and its corresponding radially projected point
cloud in 2D XY plane, in accordance with some embodiments of the present
disclosure.
[015] FIGS. 6A and 6B illustrate generation of tightest revolve
profile from a concave hull shape corresponding to each of a plurality of
faces of the B-rep CAD model, in accordance with some embodiments of
the present disclosure.
[016] FIG. 7 is a block diagram of an exemplary computer system
for implementing embodiments consistent with the present disclosure.
DETAILED DESCRIPTION
[017] Exemplary embodiments are described with reference to the
accompanying drawings. Wherever convenient, the same reference
numbers are used throughout the drawings to refer to the same or like parts.
While examples and features of disclosed principles are described herein,
modifications, adaptations, and other implementations are possible without
departing from the spirit and scope of the disclosed embodiments. It is
intended that the following detailed description be considered as exemplary
only, with the true scope and spirit being indicated by the following claims.
[018] Referring now to FIG. 1, an exemplary system 100 for
generating tightest revolve envelope for a Boundary representation (B-rep)
Computer-Aided Design (CAD) model is illustrated, in accordance with
some embodiments of the present disclosure. The system 100 may
implement an envelope generating device 101 (for example, server,
desktop, laptop, notebook, netbook, tablet, smartphone, mobile phone, or
any other computing device), in accordance with some embodiments of the
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present disclosure. The envelope generating device 101 may generate
tightest revolve envelope for a B-rep CAD model by determining a tightest
revolve profile of the BR-rep CAD model. It should be noted that, in some
embodiments, the envelope generating device 101 may determine a
concave hull shape for each of a plurality of faces of the B-rep CAD model
to identify the tightest revolve envelope.
[019] As will be described in greater detail in conjunction with
FIGS. 2 – 6A-B, the envelope generating device may receive a 2D point
cloud within an XY-plane corresponding to each of a plurality of faces of the
B-rep CAD model within an XYZ-space. The 2D point cloud includes a
plurality of discrete 2D data points within the XY-plane. The envelope
generating device may further, for each of the plurality of faces of the B-rep
CAD model, determine a concave hull shape for the 2D point cloud through
a concave hull algorithm. The envelope generating device may further
combine the concave hull shape corresponding to each of the plurality of
faces of the B-rep CAD model through at least one of a Boolean operation
and a stitching operation to obtain a tightest revolve profile of the B-rep CAD
model. The envelope generating device may further revolve the tightest
revolve profile about X-axis of the XYZ-space to obtain a tightest revolve
envelope corresponding to the B-rep CAD model.
[020] In some embodiments, the envelope generating device 101
may include one or more processors 102 and a computer-readable medium
103 (for example, a memory). The computer-readable medium 103 may
include the B-rep CAD model. Further, the computer-readable storage
medium 103 may store instructions that, when executed by the one or more
processors 102, cause the one or more processors 102 to generate the
tightest revolve envelope for the B-rep CAD model, in accordance with
aspects of the present disclosure. The computer-readable storage medium
103 may also store various data (for example, 3D point cloud, 2D point
cloud, concave hull shape corresponding to each of the plurality of faces of
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the B-rep CAD model, tightest revolve profile, and the like) that may be
captured, processed, and/or required by the system 100.
[021] The system 100 may further include a display 104. The
system 100 may interact with a user via a user interface 105 accessible via
the display 104. The system 100 may also include one or more external
devices 106. In some embodiments, the PII tracking device 101 may interact
with the one or more external devices 106 over a communication network
107 for sending or receiving various data. The external devices 106 may
include, but may not be limited to, a remote server, a digital device, or
another computing system.
[022] Referring now to FIG. 2, functional block diagram of an
exemplary system 200 for generating tightest revolve envelope for a B-rep
CAD model is illustrated, in accordance with some embodiments of the
present disclosure. The system 200 includes an envelope generating device
201. In an embodiment, the envelope generating device 201 is analogous
to the envelope generating device 101 of the system 100. The envelope
generating device 201 includes a preprocessing module 202, a point cloud
generation module 203, a concave hull computation module 204, a tightest
revolve profile generation module 205, and a tightest revolve envelope
generation module 206.
[023] The preprocessing module 202 receives a B-rep CAD model
207 as an input from a user. The B-rep CAD model 207 includes a plurality
of faces. It may be noted that the B-rep CAD model 207 may be along a first
orientation within XYZ-space. Further, the preprocessing module 202
realigns the B-rep CAD model 207 along a second orientation. In an
embodiment, the second orientation is along X-axis of global coordinate
system. The second orientation is achieved by a set of transformations
stored for later use. Further, the preprocessing module 202 identifies one or
more void regions of the B-rep CAD model 207 which are not involved in
generating the tightest revolve envelope (such as, depressions). The one or
more void regions are stored as a cluster of faces. Further, the one or more
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void regions are skipped from further processing. As will be appreciated,
skipping the one or more void regions from further processing increases
stability and robustness and improves the performance of the system 200.
Further, the preprocessing module 202 sends the B-rep CAD model 207 to
the point cloud generation module 203.
[024] The point cloud generation module 203 receives the B-rep
CAD model 207 along the second orientation from the preprocessing
module 202. The point cloud generation module 203 generates a 3D point
cloud for each of the plurality of faces of the B-rep CAD model 207 along
the second orientation. It may be noted that the 3D point cloud includes a
plurality of discrete 3D data points within the XYZ-space. Edges of each of
the plurality of faces are discretized. Further, interior of each of the plurality
of faces is discretized to obtain the 3D point cloud. Granularity of
discretization is controlled by a user-defined parameter. When the userdefined parameter is not provided by user, the parameter is internally
initialized to a value based on heuristics. It may be noted that discretizing
algorithm identifies critical points (maxima and minima of distance function)
from the plurality of discrete 3D data points required for an accurate radial
projection of a face onto a plane (such as, XY-plane).
[025] Mathematically, a radial projected point, Pr, of a given point,
P, about an axis on a plane is determined through following equation:
Pr = Pa + R*D
(1)
where,
Pa is closest point of P on user input axis;
R is magnitude of a vector joining Pa to P, i.e., R = |P – Pa|;
D is a unit vector defined by a cross product of axis direction and
plane normal through the axis, i.e., D = (Ad * Np);
Ad is a unit vector depicting user input axis direction; and
Np is a unit vector defining a normal of a plane passing through the
user input axis.
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[026] In an embodiment, the plane used for radial projection is the
XY-plane. Radially projecting each point of the 3D point cloud
corresponding to the face results into a 2D point cloud of radially projected
points lying on the XY-plane. Further, the 2D point cloud is sent to the
concave hull computation module 204.
[027] The concave hull computation module 204 receives the 2D
point cloud of the face from the point cloud generation module 203. The
concave hull computation module 204 determines a concave hull shape for
the 2D point cloud through a concave hull algorithm. The concave hull
computation module 204 identifies a set of boundary points of the 2D point
cloud through the concave hull algorithm. It may be noted that the set of
boundary points define a boundary of the face. Further, the concave hull
computation module 204 estimates a concave hull shape based on the set
of boundary points. The set of boundary points is joined appropriately to
capture a true shape of the radially projected face.
[028] A concave hull creation algorithm is based on nearest
neighbors’ approach. The concave hull computation module 204 takes the
2D point cloud on XY-plane as an input and provides a point list as an
output. The point list, when connected in sequence, generates an envelope
that optimally encloses the 2D point cloud. The concave hull computation
module 204 initializes with a first point. The first point is a minimum Y point,
i.e., a point from the 2D point cloud with minimum Y co-ordinate value.
Further, the concave hull computation module 204 finds a second point with
a maximum right hand turn angle with a reference vector from among
nearest set of neighboring points. Further, the concave hull computation
module 204 adds the second point to the concave hull and removes the
point from the 2D point cloud. Similarly, remaining points are collected till
the first point is reached. In some embodiments, checks are maintained
while adding points to the concave hull to avoid creating a self-intersecting
concave hull. Upon creating the concave hull, the concave hull computation
module 204 checks whether remaining points in the 2D point cloud are
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inside the concave hull. When one or more of the remaining points are
outside the concave hull, it is established that the concave hull is not
enclosing the 2D point cloud and the concave hull creation algorithm is
repeated by taking a bigger set of nearest neighbor points.
[029] Upon generating the set of boundary points, the concave hull
computation module 204 fits the set of boundary points to capture a true
shape of the radially projected face. As will be appreciated, a purely
sequential joining of the set of boundary points with a line segment may
result in a polygonal shaped concave hull. The polygonal shape is simple,
but generally not desirable due to large approximation error and robustness
issues of downline operations. An algorithm based on intelligent
criteria/heuristics may collect a suitable set of points to fit with a curve which
may capture the true shape of the radially projected face. In an exemplary
scenario, the face in the B-rep CAD model 207 is a revolve surface with axis
matching the user input axis. In such a scenario, shape of a radially
projected image of the face is an open curve and not enclosing an area.
Further, the concave hull computation module 204 sends the concave hull
shape to the tightest revolve profile generation module 205.
[030] The tightest revolve profile generation module 205 receives
the concave hull shape from the concave hull computation module 204. The
tightest revolve profile generation module 205 combines the concave hull
shape corresponding to each of the plurality of faces of the B-rep CAD
model 207 through at least one of a Boolean operation and a stitching
operation to obtain a tightest revolve profile of the B-rep CAD model 207.
The tightest revolve profile is obtained by adding up the radially projected
profile of each of the plurality of faces of the B-rep CAD model 207 followed
by obtaining a boundary of unified profile. Unification of profiles starts with
filtering out of closed profiles and open profiles. The closed profiles are
combined first. Further, the tightest revolve profile generation module 205
checks interaction between two profiles to decide on an addition operation.
When the two profiles inter-penetrate, the addition operation is achieved by
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the Boolean operation. When the two profiles touch or overlap, the addition
operation is achieved by stitching or sewing operation.
[031] In some embodiments, the tightest revolve profile generation
module 205 may handle near touching scenarios arising due to numerical
noise, small approximations, tolerant models, or the like. The tightest
revolve profile generation module 205 applies concept of Hausdorff distance
to identify a potential profile pair to add. Further, the tightest revolve profile
generation module 205 edits the potential profile pair, by adding suitable
vertices in one or both profiles, to make the potential profile pair compatible.
Further, the tightest revolve profile generation module 205 finally combines
the potential profile pair by stitching/sewing operation. In some
embodiments, intelligent optimizations are added to skip the addition
operation when one profile is completely enclosed inside other profile. When
each of the closed profiles is processed, the tightest revolve profile
generation module 205 starts working on the open profiles in a similar
manner as with closed profiles.
[032] When each of the closed profiles and the open profiles is
processed for the addition operation, the tightest revolve profile generation
module 205 checks whether the unified profile is closed or open. When the
unified profile is open, line segments are appropriately added to close the
unified profile. Further, the tightest revolve profile generation module 205
proceeds to simplify the unified profile based on relaxed curvature continuity
criteria to merge out edges resulting into a simplified closed profile. Further,
the tightest revolve profile generation module 205 sends the simplified
closed profile to the tightest revolve envelope generation module 206.
[033] The tightest revolve envelope generation module 206
receives the simplified closed profile the tightest revolve profile generation
module 205. Further, the tightest revolve envelope generation module 206
revolves the simplified closed profile about the X-axis to generate a revolve
model which is tightest revolve envelope 208 of the B-rep CAD model 207.
Further, the tightest revolve envelope generation module 206 realigns the
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B-rep CAD model 207 and the associated tightest revolve envelope 208
along the first orientation.
[034] It should be noted that all such aforementioned modules 202
– 206 may be represented as a single module or a combination of different
modules. Further, as will be appreciated by those skilled in the art, each of
the modules 202 – 206 may reside, in whole or in parts, on one device or
multiple devices in communication with each other. In some embodiments,
each of the modules 202 – 206 may be implemented as dedicated hardware
circuit comprising custom application-specific integrated circuit (ASIC) or
gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or
other discrete components. Each of the modules 202 – 206 may also be
implemented in a programmable hardware device such as a field
programmable gate array (FPGA), programmable array logic,
programmable logic device, and so forth. Alternatively, each of the modules
202 – 206 may be implemented in software for execution by various types
of processors (e.g., processor 102). An identified module of executable
code may, for instance, include one or more physical or logical blocks of
computer instructions, which may, for instance, be organized as an object,
procedure, function, or other construct. Nevertheless, the executables of an
identified module or component need not be physically located together, but
may include disparate instructions stored in different locations which, when
joined logically together, include the module and achieve the stated purpose
of the module. Indeed, a module of executable code could be a single
instruction, or many instructions, and may even be distributed over several
different code segments, among different applications, and across several
memory devices.
[035] As will be appreciated by one skilled in the art, a variety of
processes may be employed for generating tightest revolve envelope for a
B-rep CAD model. For example, the exemplary system 100 and the
associated envelope generating device 101 may generate tightest revolve
envelope for a B-rep CAD model by the processes discussed herein. In
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particular, as will be appreciated by those of ordinary skill in the art, control
logic and/or automated routines for performing the techniques and steps
described herein may be implemented by the system 100 and the
associated envelope generating device 101 either by hardware, software,
or combinations of hardware and software. For example, suitable code may
be accessed and executed by the one or more processors on the system
100 to perform some or all of the techniques described herein. Similarly,
application specific integrated circuits (ASICs) configured to perform some
or all of the processes described herein may be included in the one or more
processors on the system 100.
[036] Referring now to FIG. 3, an exemplary process 300 for
generating tightest revolve envelope for a B-rep CAD model is depicted via
a flowchart, in accordance with some embodiments of the present
disclosure. In an embodiment, the process 300 is implemented by the
envelope generating device 101 of the system 100. The process 300 may
be implemented by the envelope generating device 101 of the system 100.
The process 300 includes receiving the B-rep CAD model along a first
orientation within an XYZ-space from a user, at step 301. Further, the
process 300 includes aligning the B-rep CAD model from the first orientation
to a second orientation along the X-axis of the XYZ-space, at step 302.
Further, the process 300 includes identifying one or more void regions within
the B-rep CAD model having no role in the generation of the tightest revolve
envelope of the B-rep CAD model, at step 303. The one or more void
regions include a set of void discrete points.
[037] Further, the process 300 includes generating a 3D point
cloud for each of the plurality of faces of the B-rep CAD model along the
second orientation, at step 304. The 3D point cloud includes a plurality of
discrete 3D data points within the XYZ-space. The set of void discrete
points, at step 303, is not a part of the plurality of 3D data points at step 304.
Further, the process 300 includes transforming the 3D point cloud into the
2D point cloud through a radial projection of the plurality of discrete 3D data
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points within the XYZ-space upon the XY-plane to obtain the plurality of
discrete 2D data points, at step 305. By way of an example, the
preprocessing module 202 receives the B-rep CAD model 207 along the
first orientation. Further, the preprocessing module 202 aligns the B-rep
CAD model 207 along the second orientation (such as, the XY-plane). The
preprocessing module 202 identifies one or more void regions which may
not be considered for further processing. Further, the point cloud generation
module 204 receives the B-rep CAD model 207. The point cloud generation
module 204 generates a 3D point cloud corresponding to each of the
plurality of faces of the B-rep CAD model 207. Further, the point cloud
generation module 204 transforms the 3D point cloud into a 2D point cloud
through radial projection of the plurality of discrete 3D data points onto the
XY-plane.
[038] Further, the process 300 includes receiving a 2-dimensional
(2D) point cloud within an XY-plane corresponding to each of a plurality of
faces of the B-rep CAD model within an XYZ-space, at step 306. The 2D
point cloud includes a plurality of discrete 2D data points within the XYplane. Further, the process 300 includes, for each of the plurality of faces of
the B-rep CAD model, determining a concave hull shape for the 2D point
cloud through a concave hull algorithm, at step 307. Further, for each of the
plurality of faces of the B-rep CAD model, the process 300 includes
identifying a set of boundary points of the 2D point cloud through the
concave hull algorithm, at step 308. The set of boundary points is a part of
the plurality of discrete 2D data points. Further, for each of the plurality of
faces of the B-rep CAD model, the process 300 includes estimating a
concave hull shape based on the set of boundary points, at step 309.
[039] Further, for each of the set of boundary points, the process
300 includes connecting a boundary point with an adjacent boundary point
through a curve fitting technique based on a relaxed curvature continuity
criterion, at step 310. In continuation of the example above, the concave
hull computation module 204 determines a concave hull shape for each of
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the plurality of faces of the B-rep CAD model 207 through a concave hull
algorithm by identifying a set of boundary points and connecting the set of
boundary points through a curve fitting technique based on a relaxed
curvature continuity criterion.
[040] Further, the process 300 includes combining the concave
hull shape corresponding to each of the plurality of faces of the B-rep CAD
model through at least one of a Boolean operation and a stitching operation
to obtain a tightest revolve profile of the B-rep CAD model, at step 311.
[041] Further, the process 300 includes identifying one or more
open regions in the tightest revolve profile of the B-rep CAD model, at step
312. Further, the process 300 includes joining each of the one or more open
regions appropriately in the tightest revolve profile of the B-rep CAD model
through a line segment to obtain the tightest revolve profile of the B-rep CAD
model, at step 313.
[042] Further, the process 300 includes revolving the tightest
revolve profile about X-axis of the XYZ-space to obtain a tightest revolve
envelope corresponding to the B-rep CAD model, at step 314. In
continuation of the example above, the tightest revolve profile generation
module 205 generates the tightest revolve profile corresponding to the Brep CAD model 207 by combining each of concave hull shapes of the
plurality of faces. The combining may be performed through at least one of
a Boolean operation and a stitching operation. Further, the tightest revolve
profile is received by the tightest revolve envelope generation module 206.
The tightest revolve envelope generation module 206 performs a revolving
operation on the tightest revolve profile to generate the tightest revolve
envelope 208.
[043] Further, the process 300 includes realigning the tightest
revolve envelope along the first orientation within the XYZ space of the Brep CAD model, at step 315.
[044] Referring now to FIGS. 4A and FIG. 4B, a B-rep CAD model
401, tightest revolve profile 402 corresponding to the B-rep CAD model 401,
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and tightest revolve envelope 403 corresponding to the B-rep CAD model
401 are illustrated, in accordance with some embodiments of the present
disclosure. The tightest revolve envelope 403 provides a lower bound on
the stock size 404, for example turning machining operation, as shown in
FIG 4B. In FIG. 4A, the B-rep CAD model 401 is illustrated. The B-rep CAD
model 401 includes a plurality of faces. To identify the tightest revolve
envelope 403 corresponding to the B-rep CAD model 401, for each of the
plurality of faces, a 3D point cloud is generated. The 3D point cloud includes
a plurality of discrete 3D data points. Further, a 2D point cloud is derived
from the 3D point cloud by radial projection of each of the plurality of discrete
3D data points.
[045] Referring now to FIG. 4B, the tightest revolve profile 402
corresponding to the B-rep CAD model 401 is derived by determining a 2D
concave hull shape corresponding to each of the plurality of faces of the Brep CAD model 401 from the 2D point cloud. Further, 2D concave hull
shapes corresponding to the plurality of faces of the B-rep CAD model 401
are combined through an addition operation. By way of an example, the
addition operation may be a Boolean operation or a stitching operation. In
an embodiment, the adding operation is performed by the tightest revolve
profile generation module 205. Further, the tightest revolve envelope 403 is
obtained from the tightest revolve profile 402 by performing a revolving
operation on the tightest revolve profile 402. In an embodiment, the
revolving operation is performed by the tightest revolve envelope generation
module 206.
[046] Referring now to FIGS. 5A and 5B, a B-rep CAD model 500
is illustrated, in accordance with some embodiments of the present
disclosure. In FIG. 5A, the B-rep CAD model 500 is along the first
orientation. It may be noted that the first orientation is provided by the user.
The B-rep CAD model 500 includes a plurality of faces (such as, face 501).
In FIG. 5B, the B-rep CAD model 500 is along the second orientation. In an
embodiment, the second orientation is along the XY-plane. The
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preprocessing module 202 aligns the B-rep CAD model 500 along the
second orientation. Further, the point cloud generation module 203
generates a 3D point cloud for each of the plurality of faces.
[047] Referring now to FIGS. 6A and 6B, generation of tightest
revolve profile from a concave hull shape corresponding to each of a
plurality of faces of the B-rep CAD model is illustrated, in accordance with
some embodiments of the present disclosure. In FIG. 6A, a concave hull
shape (for example, the concave hull shape 601 corresponding to a face of
the B-rep CAD model) corresponding to each of a plurality of faces of the Brep CAD model is determined. In FIG. 6B, concave hull shapes
corresponding to the plurality of faces of the B-rep CAD model are combined
to form the tightest revolve profile 602 corresponding to the B-rep CAD
model. The concave hull shapes are combined through an addition
operation. By way of an example, the addition operation may be a Boolean
operation or a stitching operation.
[048] As will be also appreciated, the above described techniques
may take the form of computer or controller implemented processes and
apparatuses for practicing those processes. The disclosure can also be
embodied in the form of computer program code containing instructions
embodied in tangible media, such as floppy diskettes, solid state drives, CDROMs, hard drives, or any other computer-readable storage medium,
wherein, when the computer program code is loaded into and executed by
a computer or controller, the computer becomes an apparatus for practicing
the invention. The disclosure may also be embodied in the form of computer
program code or signal, for example, whether stored in a storage medium,
loaded into and/or executed by a computer or controller, or transmitted over
some transmission medium, such as over electrical wiring or cabling,
through fiber optics, or via electromagnetic radiation, wherein, when the
computer program code is loaded into and executed by a computer, the
computer becomes an apparatus for practicing the invention. When
implemented on a general-purpose microprocessor, the computer program
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code segments configure the microprocessor to create specific logic
circuits.
[049] The disclosed methods and systems may be implemented on
a conventional or a general-purpose computer system, such as a personal
computer (PC) or server computer. Referring now to FIG. 7, an exemplary
computing system 700 that may be employed to implement processing
functionality for various embodiments (e.g., as a SIMD device, client device,
server device, one or more processors, or the like) is illustrated. Those
skilled in the relevant art will also recognize how to implement the invention
using other computer systems or architectures. The computing system 700
may represent, for example, a user device such as a desktop, a laptop, a
mobile phone, personal entertainment device, DVR, and so on, or any other
type of special or general-purpose computing device as may be desirable
or appropriate for a given application or environment. The computing
system 700 may include one or more processors, such as a processor 701
that may be implemented using a general or special purpose processing
engine such as, for example, a microprocessor, microcontroller or other
control logic. In this example, the processor 701 is connected to a bus 702
or other communication medium. In some embodiments, the processor 701
may be an Artificial Intelligence (AI) processor, which may be implemented
as a Tensor Processing Unit (TPU), or a graphical processor unit, or a
custom programmable solution Field-Programmable Gate Array (FPGA).
[050] The computing system 700 may also include a memory 703
(main memory), for example, Random Access Memory (RAM) or other
dynamic memory, for storing information and instructions to be executed by
the processor 701. The memory 703 also may be used for storing temporary
variables or other intermediate information during execution of instructions
to be executed by the processor 701. The computing system 700 may
likewise include a read only memory (“ROM”) or other static storage device
coupled to bus 702 for storing static information and instructions for the
processor 701.
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[051] The computing system 700 may also include a storage device
704, which may include, for example, a media drives 705 and a removable
storage interface. The media drive 705 may include a drive or other
mechanism to support fixed or removable storage media, such as a hard
disk drive, a floppy disk drive, a magnetic tape drive, an SD card port, a
USB port, a micro USB, an optical disk drive, a CD or DVD drive (R or RW),
or other removable or fixed media drive. A storage media 706 may include,
for example, a hard disk, magnetic tape, flash drive, or other fixed or
removable medium that is read by and written to by the media drive 705. As
these examples illustrate, the storage media 706 may include a computerreadable storage medium having stored there in particular computer
software or data.
[052] In alternative embodiments, the storage devices 704 may
include other similar instrumentalities for allowing computer programs or
other instructions or data to be loaded into the computing system 700. Such
instrumentalities may include, for example, a removable storage unit 707
and a storage unit interface 708, such as a program cartridge and cartridge
interface, a removable memory (for example, a flash memory or other
removable memory module) and memory slot, and other removable storage
units and interfaces that allow software and data to be transferred from the
removable storage unit 707 to the computing system 700.
[053] The computing system 700 may also include a
communications interface 709. The communications interface 709 may be
used to allow software and data to be transferred between the computing
system 700 and external devices. Examples of the communications
interface 709 may include a network interface (such as an Ethernet or other
NIC card), a communications port (such as for example, a USB port, a micro
USB port), Near field Communication (NFC), etc. Software and data
transferred via the communications interface 709 are in the form of signals
which may be electronic, electromagnetic, optical, or other signals capable
of being received by the communications interface 709. These signals are
Docket No.: IIP-HCL-P0054
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provided to the communications interface 709 via a channel 710. The
channel 710 may carry signals and may be implemented using a wireless
medium, wire or cable, fiber optics, or other communications medium. Some
examples of the channel 710 may include a phone line, a cellular phone
link, an RF link, a Bluetooth link, a network interface, a local or wide area
network, and other communications channels.
[054] The computing system 700 may further include Input/Output
(I/O) devices 711. Examples may include, but are not limited to a display,
keypad, microphone, audio speakers, vibrating motor, LED lights, etc. The
I/O devices 711 may receive input from a user and also display an output of
the computation performed by the processor 701. In this document, the
terms “computer program product” and “computer-readable medium” may
be used generally to refer to media such as, for example, the memory 703,
the storage devices 704, the removable storage unit 707, or signal(s) on the
channel 710. These and other forms of computer-readable media may be
involved in providing one or more sequences of one or more instructions to
the processor 701 for execution. Such instructions, generally referred to as
“computer program code” (which may be grouped in the form of computer
programs or other groupings), when executed, enable the computing
system 700 to perform features or functions of embodiments of the present
invention.
[055] In an embodiment where the elements are implemented
using software, the software may be stored in a computer-readable medium
and loaded into the computing system 700 using, for example, the
removable storage unit 707, the media drive 705 or the communications
interface 709. The control logic (in this example, software instructions or
computer program code), when executed by the processor 701, causes the
processor 701 to perform the functions of the invention as described herein.
[056] Thus, the disclosed method and system try to overcome the
technical problem of generating tightest revolve envelope for a B-rep CAD
model. The method and system provide an automated mechanism to
Docket No.: IIP-HCL-P0054
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compute the tightest revolve envelope for a B-rep CAD model about a given
direction. Further, the method and system provide for a robust solution that
may handle any part profile (from simple to complex) and may be ported
into any software based on solid modeling. Further, the method and system
incorporate intelligent optimizations to reduce computational load and
provide an automated mechanism to accurately predict stock size for turning
operation. Further, the method and system may be used in costing domain
to predict cost of manufacturing the part, packaging industry for 3D nesting
of parts, and analysis domain for analysis.
[057] As will be appreciated by those skilled in the art, the
techniques described in the various embodiments discussed above are not
routine, or conventional, or well understood in the art. The techniques
discussed above provide for generating tightest revolve envelope for a Brep CAD model. The techniques first receive a 2D point cloud within an XYplane corresponding to each of a plurality of faces of the B-rep CAD model
within an XYZ-space. The 2D point cloud includes a plurality of discrete 2D
data points within the XY-plane. For each of the plurality of faces of the Brep CAD model, the techniques then determine a concave hull shape for the
2D point cloud through a concave hull algorithm. The techniques then
combine the concave hull shape corresponding to each of the plurality of
faces of the B-rep CAD model through at least one of a Boolean operation
and a stitching operation to obtain a tightest revolve profile of the B-rep CAD
model. The techniques then revolve the tightest revolve profile about X-axis
of the XYZ-space to obtain a tightest revolve envelope corresponding to the
B-rep CAD model.
[058] In light of the above mentioned advantages and the technical
advancements provided by the disclosed method and system, the claimed
steps as discussed above are not routine, conventional, or well understood
in the art, as the claimed steps enable the following solutions to the existing
problems in conventional technologies. Further, the claimed steps clearly
Docket No.: IIP-HCL-P0054
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bring an improvement in the functioning of the device itself as the claimed
steps provide a technical solution to a technical problem.
[059] The specification has described method and system for
generating tightest revolve envelope for a B-rep CAD model. The illustrated
steps are set out to explain the exemplary embodiments shown, and it
should be anticipated that ongoing technological development will change
the manner in which particular functions are performed. These examples
are presented herein for purposes of illustration, and not limitation. Further,
the boundaries of the functional building blocks have been arbitrarily defined
herein for the convenience of the description. Alternative boundaries can be
defined so long as the specified functions and relationships thereof are
appropriately performed. Alternatives (including equivalents, extensions,
variations, deviations, etc., of those described herein) will be apparent to
persons skilled in the relevant art(s) based on the teachings contained
herein. Such alternatives fall within the scope and spirit of the disclosed
embodiments.
[060] Furthermore, one or more computer-readable storage media
may be utilized in implementing embodiments consistent with the present
disclosure. A computer-readable storage medium refers to any type of
physical memory on which information or data readable by a processor may
be stored. Thus, a computer-readable storage medium may store
instructions for execution by one or more processors, including instructions
for causing the processor(s) to perform steps or stages consistent with the
embodiments described herein. The term “computer-readable medium”
should be understood to include tangible items and exclude carrier waves
and transient signals, i.e., be non-transitory. Examples include random
access memory (RAM), read-only memory (ROM), volatile memory,
nonvolatile memory, hard drives, CD ROMs, DVDs, flash drives, disks, and
any other known physical storage media.
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[061] It is intended that the disclosure and examples be
considered as exemplary only, with a true scope and spirit of disclosed
embodiments being indicated by the following claims.

CLAIMS
WHAT IS CLAIMED IS:
1. A method (300) for generating tightest revolve envelope (403) for a
Boundary representation (B-rep) Computer-Aided Design (CAD) model
(401), the method (300) comprising:
receiving (306), by an envelope generating device (101), a 2-
dimensional (2D) point cloud within an XY-plane corresponding to each of
a plurality of faces of the B-rep CAD model (401) within an XYZ-space,
wherein the 2D point cloud comprises a plurality of discrete 2D data points
within the XY-plane;
for each of the plurality of faces of the B-rep CAD model (401),
determining (307), by the envelope generating device (101), a concave
hull shape (601) for the 2D point cloud through a concave hull algorithm;
combining (311), by the envelope generating device (101), the
concave hull shape (601) corresponding to each of the plurality of faces of
the B-rep CAD model (401) through at least one of a Boolean operation
and a stitching operation to obtain a tightest revolve profile (402) of the Brep CAD model (401); and
revolving (314), by the envelope generating device (101), the
tightest revolve profile (402) about X-axis of the XYZ-space to obtain a
tightest revolve envelope (403) corresponding to the B-rep CAD model
(401).
2. The method of claim 1, further comprising:
receiving (301) the B-rep CAD model (401) along a first orientation
within an XYZ-space from a user;
realigning (302) the B-rep CAD model (401) from the first
orientation to a second orientation along the X-axis of the XYZ-space; and
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generating (304) a 3-dimensional (3D) point cloud for each of the
plurality of faces of the B-rep CAD model (401) along the second
orientation, wherein the 3D point cloud comprises a plurality of discrete 3D
data points within the XYZ-space; and
transforming (305) the 3D point cloud into the 2D point cloud
through a radial projection of the plurality of discrete 3D data points within
the XYZ-space upon the XY-plane to obtain the plurality of discrete 2D
data points.
3. The method of claim 2, further comprising identifying (303) one or
more void regions within the B-rep CAD model (401) having no role in the
generation of the tightest revolve envelope (403) of the B-rep CAD model
(401), wherein the one or more void regions comprise a set of void
discrete points, and wherein the set of void discrete points is not a part of
the plurality of 3D data points.
4. The method of claim 2, further comprising realigning (315) the tightest
revolve envelope (403) along the first orientation within the XYZ space of
the B-rep CAD model (401).
5. The method of claim 1, wherein determining (307) the concave hull
shape for the 2D point cloud further comprises:
for each of the plurality of faces of the B-rep CAD model (401),
identifying (308) a set of boundary points of the 2D point
cloud through the concave hull algorithm, wherein the set of
boundary points is a part of the plurality of discrete 2D data points;
and
estimating (309) a concave hull shape (601) based on the
set of boundary points; and
Docket No.: IIP-HCL-P0054
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for each of the set of boundary points, connecting (310) a
boundary point with an adjacent boundary point through a curve
fitting technique based on a relaxed curvature continuity criterion.
6. The method of claim 1, further comprising:
identifying (312) one or more open regions in the tightest revolve
profile (402) of the B-rep CAD model (401); and
joining (313) each of the one or more open regions appropriately in
the tightest revolve profile (402) of the B-rep CAD model (401) through a
line segment to obtain the tightest revolve profile (402) of the B-rep CAD
model (401).
7. A system (200) for generating tightest revolve envelope (403) for a
Computer-Aided Design (CAD) Boundary representation (B-rep) model
(401), the system (200) comprising:
a processor (102); and
a memory communicatively coupled to the processor (102), wherein
the memory stores processor instructions, which when executed by the
processor (102), cause the processor (102) to:
receive (306) a 2-dimensional (2D) point cloud within an XYplane corresponding to each of a plurality of faces of the B-rep CAD model
(401) within an XYZ-space, wherein the 2D point cloud comprises a
plurality of discrete 2D data points within the XY-plane;
for each of the plurality of faces of the B-rep CAD model
(401), determine (307) a concave hull shape (601) for the 2D point cloud
through a concave hull algorithm;
combine (311) the concave hull shape (601) corresponding
to each of the plurality of faces of the B-rep CAD model (401) through at
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least one of a Boolean operation and a stitching operation to obtain a
tightest revolve profile (402) of the B-rep CAD model (401); and
revolve (314) the tightest revolve profile (402) about X-axis of
the XYZ-space to obtain a tightest revolve envelope (403) corresponding
to the B-rep CAD model (401).
8. The system of claim 7, wherein the processor instructions, on
execution, further cause the processor (102) to:
receive (301) the B-rep CAD model (401) along a first orientation
within an XYZ-space from a user;
realign (302) the B-rep CAD model (401) from the first orientation to
a second orientation along the X-axis of the XYZ-space; and
generate (304) a 3-dimensional (3D) point cloud for each of the
plurality of faces of the B-rep CAD model (401) along the second
orientation, wherein the 3-dimensional point cloud comprises a plurality of
discrete 3D data points within the XYZ-space; and
transform (305) the 3D point cloud into the 2D point cloud through a
radial projection of the plurality of discrete 3D data points within the XYZspace upon the XY-plane to obtain the plurality of discrete 2D data points.
9. The system of claim 8, wherein the processor instructions, on
execution, further cause the processor (102) to realign (315) the tightest
revolve envelope (403) along the first orientation within the XYZ space of
the B-rep CAD model (401).
10. The system of claim 7, wherein to determine (307) the concave hull
shape (601) for the 2D point cloud, the processor instructions, on
execution, further cause the processor (102) to:
for each of the plurality of faces of the B-rep CAD model (401),
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identify (308) a set of boundary points of the 2D point cloud
through the concave hull algorithm, wherein the set of boundary
points is a part of the plurality of discrete 2D data points; and
estimate (309) a concave hull shape (601) based on the set
of boundary points; and
for each of the set of boundary points, connect (310) a
boundary point with an adjacent boundary point through a curve
fitting technique based on a relaxed curvature continuity criterion.