Operator Reference
simplify_object_model_3d (Operator)
simplify_object_model_3d — Simplify a triangulated 3D object model.
Signature
simplify_object_model_3d( : : ObjectModel3D, Method, Amount, GenParamName, GenParamValue : SimplifiedObjectModel3D)
Description
simplify_object_model_3d simplifies the triangulated 3D object model
ObjectModel3D by removing model points and
returns the result in SimplifiedObjectModel3D. Note that in
contrast to sample_object_model_3d points are removed
such that the original geometry of the object model is represented as good
as possible. Typically, this means that edges are preserved while the
point density within smooth parts is reduced.
This might be helpful, for example, to speed up subsequent operator calls
by using a 3D object model of reduced complexity.
The triangulation of the input 3D object model is preserved as opposed to
the operator sample_object_model_3d, which samples surfaces to
equidistant unconnected 3D points.
Currently, the operator offers only a single simplification method
('preserve_point_coordinates'), which can be set in
Method. This method ensures that the points in the
simplified object model SimplifiedObjectModel3D have the same
coordinates as the respective points in the input object model
ObjectModel3D.
simplify_object_model_3d only works for triangulated object models.
Whether an object model contains a triangulation can be queried with
get_object_model_3d_params
(GenParamName='has_triangles'). Object models that
do not contain a triangulation must be triangulated beforehand, e.g., by
using triangulate_object_model_3d or prepare_object_model_3d
(Purpose='segmentation').
The degree of simplification can be set with Amount. By default,
Amount specifies the percentage of points of the input object
model that should be contained in the output object model. Thus, the
smaller the value of Amount in this case is chosen the
stronger the object model will be simplified.
Alternatively, the meaning of the parameter Amount can be
modified. For this, the generic parameter 'amount_type' can
be set to one of the following values:
- 'percentage_remaining' (default):
-
Amountspecifies the percentage of points of the input object model that should be contained in the output object model.Value range: [0.0 ... 100.0].
- 'percentage_to_remove':
-
Amountspecifies the percentage of points of the input object model that should be removed.Value range: [0.0 ... 100.0].
- 'num_points_remaining':
-
Amountspecifies the number of points of the input object model that should be contained in the output object model.Value range: [0 ... number of points in the input object model].
- 'num_points_to_remove':
-
Amountspecifies the number of points of the input object model that should be removed.Value range: [0 ... number of points in the input object model].
Sometimes triangular meshes flip during the simplification, i.e., the
direction of their normal vectors changes by 180 degrees. This
especially happens for artificially created CAD models that consist of
planar parts. To avoid this flipping, the generic
parameter 'avoid_triangle_flips' can be set to 'true'
(the default is 'false'). Note that in this case, the run-time of
simplify_object_model_3d will increase.
Note that multiple calls of simplify_object_model_3d with a
lower degree of simplification might result in a different simplified
object model compared to a single call with a higher degree of
simplification. Also note that isolated (i.e., non-triangulated) points
will be removed. This might result in a number of points in
SimplifiedObjectModel3D that slightly deviates from the degree of
simplification that is specified in Amount.
Execution Information
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Processed without parallelization.
Parameters
ObjectModel3D (input_control) object_model_3d(-array) → (handle)
Handle of the 3D object model that should be simplified.
Method (input_control) string → (string)
Method that should be used for simplification.
Default: 'preserve_point_coordinates'
List of values: 'preserve_point_coordinates'
Amount (input_control) number → (real / integer)
Degree of simplification (default: percentage of remaining model points).
GenParamName (input_control) attribute.name-array → (string)
Names of the generic parameters.
Default: []
List of values: 'amount_type', 'avoid_triangle_flips'
GenParamValue (input_control) attribute.value-array → (string / real)
Values of the generic parameters.
Default: []
Suggested values: 'percentage_remaining', 'percentage_to_remove', 'num_points_remaining', 'num_points_to_remove', 'true', 'false'
SimplifiedObjectModel3D (output_control) object_model_3d(-array) → (handle)
Handle of the simplified 3D object model.
Example (HDevelop)
read_object_model_3d ('mvtec_bunny.om3', 'm', [], [], ObjectModel3D, Status)
visualize_object_model_3d (WindowHandle, ObjectModel3D, [], [], [], [], \
[], [], [], Pose)
simplify_object_model_3d (ObjectModel3D, 'preserve_point_coordinates', \
5.0, 'amount_type', 'percentage_remaining', \
SimplifiedObjectModel3D)
visualize_object_model_3d (WindowHandle, SimplifiedObjectModel3D, [], \
Pose, [], [], [], [], [], Pose)
Result
simplify_object_model_3d returns 2 (
H_MSG_TRUE)
if all parameters are
correct. If necessary, an exception is raised.
Possible Predecessors
prepare_object_model_3d,
read_object_model_3d,
triangulate_object_model_3d,
xyz_to_object_model_3d
Possible Successors
disp_object_model_3d,
smallest_bounding_box_object_model_3d
Alternatives
sample_object_model_3d,
smooth_object_model_3d
References
Michael Garland, Paul S. Heckbert: Surface Simplification Using Quadric Error Metrics, Proceedings of the 24th Annual Conference on Computer Graphics and Interactive Techniques (SIGGRAPH '97), 209-216, ACM Press, 1997
Module
3D Metrology