123 lines
5.3 KiB
C++
123 lines
5.3 KiB
C++
/****************************************************************************
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* VCGLib o o *
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* Visual and Computer Graphics Library o o *
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* _ O _ *
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* Copyright(C) 2004-2012 \/)\/ *
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* Visual Computing Lab /\/| *
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* ISTI - Italian National Research Council | *
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* \ *
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* All rights reserved. *
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* *
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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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* *
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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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* *
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****************************************************************************/
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/*! \file trimesh_inertia.cpp
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\ingroup code_sample
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\brief An example of computing the inertia properties of meshes
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Two meshes are created a rectangular box and a torus and their mass properties are computed and shown.
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The result should match the closed formula for these objects (with a reasonable approximation)
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*/
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#include<vcg/complex/complex.h>
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#include<wrap/io_trimesh/import_off.h>
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#include<vcg/complex/algorithms/inertia.h>
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#include<vcg/complex/algorithms/create/platonic.h>
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class MyEdge;
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class MyFace;
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class MyVertex;
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struct MyUsedTypes : public vcg::UsedTypes< vcg::Use<MyVertex> ::AsVertexType,
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vcg::Use<MyEdge> ::AsEdgeType,
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vcg::Use<MyFace> ::AsFaceType>{};
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class MyVertex : public vcg::Vertex<MyUsedTypes, vcg::vertex::Coord3f, vcg::vertex::Normal3f, vcg::vertex::BitFlags >{};
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class MyFace : public vcg::Face< MyUsedTypes, vcg::face::FFAdj, vcg::face::Normal3f, vcg::face::VertexRef, vcg::face::BitFlags > {};
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class MyEdge : public vcg::Edge<MyUsedTypes>{};
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class MyMesh : public vcg::tri::TriMesh< std::vector<MyVertex>, std::vector<MyFace> , std::vector<MyEdge> > {};
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int main( int argc, char **argv )
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{
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MyMesh boxMesh,torusMesh;
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vcg::Matrix33f IT;
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vcg::Point3f ITv;
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vcg::tri::Hexahedron(boxMesh);
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vcg::Matrix44f ScaleM,TransM;
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ScaleM.SetScale(1.0f, 2.0f, 5.0f);
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TransM.SetTranslate(2.0f,3.0f,4.0f);
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vcg::tri::UpdatePosition<MyMesh>::Matrix(boxMesh,ScaleM);
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vcg::tri::UpdatePosition<MyMesh>::Matrix(boxMesh,TransM);
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vcg::tri::Inertia<MyMesh> Ib(boxMesh);
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vcg::Point3f cc = Ib.CenterOfMass();
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Ib.InertiaTensorEigen(IT,ITv);
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printf("Box of size 2,4,10, centered in (2,3,4)\n");
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printf("Volume %f \n",Ib.Mass());
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printf("CenterOfMass %f %f %f\n",cc[0],cc[1],cc[2]);
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printf("InertiaTensor Values %6.3f %6.3f %6.3f\n",ITv[0],ITv[1],ITv[2]);
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printf("InertiaTensor Matrix\n");
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printf(" %6.3f %6.3f %6.3f\n",IT[0][0],IT[0][1],IT[0][2]);
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printf(" %6.3f %6.3f %6.3f\n",IT[1][0],IT[1][1],IT[1][2]);
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printf(" %6.3f %6.3f %6.3f\n",IT[2][0],IT[2][1],IT[2][2]);
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// Now we have a box with sides (h,w,d) 2,4,10, centered in (2,3,4)
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// Volume is 80
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// inertia tensor should be:
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// I_h = 1/12 m *(w^2+d^2) = 1/12 * 80 * (16+100) = 773.33
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// I_w = 1/12 m *(h^2+d^2) = 1/12 * 80 * (4+100) = 693.33
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// I_d = 1/12 m *(h^2+w^2) = 1/12 * 80 * (4+16) = 133.33
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vcg::tri::Torus(torusMesh,2,1,1024,512);
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vcg::tri::Inertia<MyMesh> It(torusMesh);
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cc = It.CenterOfMass();
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It.InertiaTensorEigen(IT,ITv);
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printf("\nTorus of radius 2,1\n");
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printf("Mass %f \n",It.Mass());
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printf("CenterOfMass %f %f %f\n",cc[0],cc[1],cc[2]);
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printf("InertiaTensor Values %6.3f %6.3f %6.3f\n",ITv[0],ITv[1],ITv[2]);
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printf("InertiaTensor Matrix\n");
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printf(" %6.3f %6.3f %6.3f\n",IT[0][0],IT[0][1],IT[0][2]);
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printf(" %6.3f %6.3f %6.3f\n",IT[1][0],IT[1][1],IT[1][2]);
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printf(" %6.3f %6.3f %6.3f\n",IT[2][0],IT[2][1],IT[2][2]);
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/*
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Now we have a torus with c = 2, a = 1
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c = radius of the ring
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a = radius of the section
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Volume is:
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V= 2 PI^2 * a^2 * c = ~39.478
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Inertia tensor should be:
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| ( 5/8 a^2 + 1/2 c^2 ) M 0 0 |
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| 0 ( 5/8 a^2 + 1/2 c^2 ) M 0 | =
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| 0 0 (3/4 a^2 + c^2) M |
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| ( 5/8+2 ) M 0 0 | | 103.630 0 0 |
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= | 0 ( 5/8+2 ) M 0 | = | 0 103.630 0 |
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| 0 0 (3/4+2) M | | 0 0 187.52 |
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*/
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return 0;
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}
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