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Do not use inertia during mesh compilation.

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Fixes #2479.

PiperOrigin-RevId: 735387473
Change-Id: Ib241f2a0efc100bbe2cec24e0399bfcc87268094
This commit is contained in:
Alessio Quaglino
2025-03-10 08:34:38 -07:00
committed by Copybara-Service
parent e7a715497e
commit 14dc6fd33b
4 changed files with 65 additions and 50 deletions
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src/user/user_mesh.cc
+10 -10
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@@ -1517,8 +1517,6 @@ void mjCMesh::Process() {
// find centroid of faces
ComputeFaceCentroid(facecen);
double density = model->def_map[classname]->Geom().density;
// compute inertia and transform mesh. The mesh is transformed such that it is
// centered at the CoM and the axes are the principle axes of inertia
double CoM[3] = {0, 0, 0};
@@ -1565,20 +1563,22 @@ void mjCMesh::Process() {
}
// compute sizes of equivalent inertia box
double mass = GetVolumeRef() * density;
double volume = GetVolumeRef();
double* boxsz = GetInertiaBoxPtr();
boxsz[0] = sqrt(6*(eigval[1]+eigval[2]-eigval[0])/mass)/2;
boxsz[1] = sqrt(6*(eigval[0]+eigval[2]-eigval[1])/mass)/2;
boxsz[2] = sqrt(6*(eigval[0]+eigval[1]-eigval[2])/mass)/2;
boxsz[0] = sqrt(6*(eigval[1]+eigval[2]-eigval[0])/volume)/2;
boxsz[1] = sqrt(6*(eigval[0]+eigval[2]-eigval[1])/volume)/2;
boxsz[2] = sqrt(6*(eigval[0]+eigval[1]-eigval[2])/volume)/2;
// transform CoM to origin
Transform(CoM, quattmp);
}
// compute abstract (unitless) inertia
void mjCMesh::ComputeInertia(double inert[6], double CoM[3]) {
double nrm[3];
double cen[3];
double density = model->def_map[classname]->Geom().density;
// copy vertices to avoid modifying the original mesh
std::vector<double> vert_centered(vert_);
@@ -1613,11 +1613,11 @@ void mjCMesh::ComputeInertia(double inert[6], double CoM[3]) {
// apply formula, accumulate
GetVolumeRef() += vol;
for (int j=0; j<6; j++) {
P[j] += density*vol /
P[j] += vol /
(inertia == mjMESH_INERTIA_SHELL ? 12 : 20) * (
2*(D[k[j][0]] * D[k[j][1]] +
E[k[j][0]] * E[k[j][1]] +
F[k[j][0]] * F[k[j][1]]) +
E[k[j][0]] * E[k[j][1]] +
F[k[j][0]] * F[k[j][1]]) +
D[k[j][0]] * E[k[j][1]] + D[k[j][1]] * E[k[j][0]] +
D[k[j][0]] * F[k[j][1]] + D[k[j][1]] * F[k[j][0]] +
E[k[j][0]] * F[k[j][1]] + E[k[j][1]] * F[k[j][0]]);