77 lines
3.6 KiB
Plaintext
77 lines
3.6 KiB
Plaintext
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VCGLib http://vcg.sf.net o o
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Visual and Computer Graphics Library o o
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_ O _
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Copyright(C) 2005-2006 \/)\/
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Visual Computing Lab http://vcg.isti.cnr.it /\/|
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ISTI - Italian National Research Council |
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\
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TriDecimator 1.00 2/10/2005
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All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License (http://www.gnu.org/licenses/gpl.txt)
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for more details.
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--- Synopsis ---
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tridecimator fileIn fileOut face_num [opt]\
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Where opt can be:\
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-e# QuadricError threshold (range [0,inf) default inf)
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-b# Boundary Weight (default .5)
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-q# Quality threshold (range [0.0, 0.866], default .3 )
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-n# Normal threshold (degree range [0,180] default 90)
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-E# Minimal admitted quadric value (default 1e-15, must be >0)
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-Q[y|n] Use or not Quality Threshold (default yes)
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-N[y|n] Use or not Normal Threshold (default no)
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-A[y|n] Use or not Area Weighted Quadrics (default yes)
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-O[y|n] Use or not vertex optimal placement (default yes)
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-S[y|n] Use or not Scale Independent quadric measure(default yes)
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-B[y|n] Preserve or not mesh boundary (default no)
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-T[y|n] Preserve or not Topology (default no)
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-H[y|n] Use or not Safe Heap Update (default no)
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-P Before simplification, remove duplicate & unreferenced vertices
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Supported formats: PLY, OFF, STL
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-- Some technical notes --
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This simplification tool employ a quadric error based edge collapse iterative approach.
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Each possible collapse is scored taking into account
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- its quadric error
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- its quadric boundary error
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- the normal variation caused by the collapse itself
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- the future quality (aspect ratio) of the triangles involved in the collapse
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The simplification can ends when the desired number of triangles has been reached.
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The 'Safe Heap Update' change the set of edges re-inserted in the heap
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after a collapse resulting in a vertex v; this option put back in the
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heap not only incident in the vbut all the edges of the triangles incident
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in v. It slows down a lot.
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The 'Scale Independent quadric' is useful when you want simplify
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two different meshes at the same 'error'; otherwise the quadric
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error used in the heap is somewhat normalized and independent
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of the size of the mesh.
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The Normal threshold avoid to make large changes in variation of the normal
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of the surfaces, but on the other hand it prevent the removal of small 'folded'
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triangles that can be already present. Therefore in most cases is not very useful.
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Cleaning the mesh is mandatory for some input format like STL that always
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duplicates all the vertices.
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