DecimateGeom

DESCRIPTION

This module reduces the number of triangles in the geometry by removing vertices in regions of the surface with low curvature.

It is an implementation of the method descibed in the paper: Decimation of Triangle Meshes. W.J. Schroeder, J.A. Zarge and W.E. Lorensen Computer Graphics 26, p. 26, 1992

At this moment the module can only handle geometries build from IndexedTriangleStripSets (Explorer or Inventor type).

Written by: Wilfred Janssen wilfred@sara.nl Visualization Center Academic Computing Services Amsterdam (SARA) Amsterdam, The Netherlands.

INPUTS

Port: Input
Type: Geometry
This is the incoming geometry that needs to be simplified.

WIDGETS

Port: decimation
Type: Dial
This is the decimation parameter. It determines the tolerance of the algorithm. When the decimation parameter is 0.0 only vertices are removed that are in flat parts of the surface. For higher decimation parameters more vertices are removed. The decimation parameter is, in fact, the maximum distance a vertex can have to the average plane through neighboring vertices to be a candidate for removal.

Port: convergence
Type: Dial
This decimation is an iterative procedure. In each pass the number of removed vertices gets smaller until in the last pass no vertices are removed. It can take a large number of passes before full convergence is reached, especially for large geometries. With this parameter a convergence limit can be set. Convergence=0.0 means full convergence.

Port: reduction
Type: Text
This is in fact an output parameter that return the reduction in the number of vertices.

Port: feature_angle
Type: Dial
If the angle between adjacent triangles is larger then this angle (in degrees) the edge between the triangles is considered a feature edge en is conserved if the keep_features option is on.

Port: keep_features
Type: Option Menu
Menu Item: No
Menu Item: Yes
This option determines whether sharp edges should be preserved in the decimation process.

Port: print_debug
Type: Radio Box
Menu Item: quiet
Menu Item: informative
Menu Item: noisy (debugging)
With this parameter the amount of information printed by the module can be controlled.

OUTPUTS

Port: Output
Type: Geometry
This is the resulting geometry with the reduced number of triangles.

PROBLEMS

At this moment the module can only handle geometries build from IndexedTriangleStripSets (Explorer or Inventor type).

SEE ALSO

SmoothGeom
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© The Numerical Algorithms Group Ltd, Oxford UK. 1996