diff --git a/apps/tridecimator/readme.txt b/apps/tridecimator/readme.txt index 86d407d6..b15eca5c 100644 --- a/apps/tridecimator/readme.txt +++ b/apps/tridecimator/readme.txt @@ -6,7 +6,7 @@ Visual Computing Lab http://vcg.isti.cnr.it /\/| ISTI - Italian National Research Council | \ - Metro 4.05 04/05/2005 + TriDecimator 1.00 2/10/2005 All rights reserved. @@ -24,59 +24,53 @@ for more details. --- Synopsis --- -Metro is a tool designed to evaluate the difference between two triangular meshes. -Metro adopts an approximated approach based on surface sampling and point-to-surface distance computation. -Please, when using this tool, cite the following reference: +tridecimator fileIn fileOut face_num [opt]\ +Where opt can be:\ + -e# QuadricError threshold (range [0,inf) default inf) + -b# Boundary Weight (default .5) + -q# Quality threshold (range [0.0, 0.866], default .3 ) + -n# Normal threshold (degree range [0,180] default 90) + -E# Minimal admitted quadric value (default 1e-15, must be >0) + -Q[y|n] Use or not Quality Threshold (default yes) + -N[y|n] Use or not Normal Threshold (default no) + -A[y|n] Use or not Area Weighted Quadrics (default yes) + -O[y|n] Use or not vertex optimal placement (default yes) + -S[y|n] Use or not Scale Independent quadric measure(default yes) + -B[y|n] Preserve or not mesh boundary (default no) + -T[y|n] Preserve or not Topology (default no) + -H[y|n] Use or not Safe Heap Update (default no) + -P Before simplification, remove duplicate & unreferenced vertices + +Supported formats: PLY, OFF, STL -P. Cignoni, C. Rocchini and R. Scopigno -"Metro: measuring error on simplified surfaces" -Computer Graphics Forum, Blackwell Publishers, vol. 17(2), June 1998, pp 167-174 -Available at http://vcg.sf.net +-- Some technical notes -- + +This simplification tool employ a quadric error based edge collapse iterative approach. +Each possible collapse is scored taking into account +- its quadric error +- its quadric boundary error +- the normal variation caused by the collapse itself +- the future quality (aspect ratio) of the triangles involved in the collapse + +The simplification can ends when the desired number of triangles has been reached. + +The 'Safe Heap Update' change the set of edges re-inserted in the heap +after a collapse resulting in a vertex v; this option put back in the +heap not only incident in the vbut all the edges of the triangles incident +in v. It slows down a lot. + +The 'Scale Independent quadric' is useful when you want simplify +two different meshes at the same 'error'; otherwise the quadric +error used in the heap is somewhat normalized and independent +of the size of the mesh. + +The Normal threshold avoid to make large changes in variation of the normal +of the surfaces, but on the other hand it prevent the removal of small 'folded' +triangles that can be already present. Therefore in most cases is not very useful. + +Cleaning the mesh is mandatory for some input format like STL that always +duplicates all the vertices. -You can find some sample mesh to test in the 'Metro Sample dataset' package downloadable from sourceforge. - -For any question about this software please contact: -Paolo Cignoni ( p.cignoni@isti.cnr.it ) - ---- General Info --- - -Metro is a tool designed to evaluate the difference between two triangular meshes. -Metro adopts an approximated approach based on surface sampling and point-to-surface distance computation. -Three different surface sampling methods are implemented: - - * Montecarlo sampling (pick k random samples in the interior of each face) - * Subdivision sampling (recursively subdivide each face along the longest edge and choose the sample in the center of each cell) - * Similar Triangles sampling (subdivide each face F in k polygons similar to F and sample the face in correspondence with the vertices of these polygons, internal to F) - -Note that the three methods described above are used to sample only the interior of each face. -A different scheme is used to sample vertices and edges: vertices are sampled in the straightforward manner, -while edges are sampled by uniformly interleaving samples along each edge. - ---- Basic usage --- - -Metro is a command-line tool which allows the user to select among different sampling schemes. -A list of the command-line parameters accepted by the tool is shown in the following. - -Usage: Metro file1 file2 [opts] - -where "file1" and "file2" are the input meshes in PLY, OFF or STL format, and opts can be: - - -v disable vertex sampling - -e disable edge sampling - -f disable face sampling - -u does not ignore unreferred vertices and sample also unreferenced vertices - (useful for sampling point clouds against meshes) - -sx set the face sampling mode - where x can be: - -S0 montecarlo sampling - -S1 subdivision sampling - -S2 similar triangles sampling (Default) - -n# set the required number of samples (overrides -a) - -a# set the required number of samples per area unit (overrides -n) - -c save computed error as vertex colour and quality in two ply files - -C # # Set the min/max values used for color mapping (useful for taking snapshot with coherent color ramp) - -L Remove duplicated and unreferenced vertices before processing to avoid - -H write files with histograms of error distribution \ No newline at end of file