chenlin/Mujoco_WASM
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Optimize flex by pinning nodes in empty cells.

Browse Source 
This change introduces an optimization for flexcomp objects defined by a mesh. It identifies grid cells that do not contain any mesh vertices and marks them as empty. Nodes that are exclusively part of empty cells are pinned, preventing them from moving. Stiffness computations are skipped for empty cells, reducing computational cost. The total mass is now distributed only among the non-pinned nodes.

PiperOrigin-RevId: 902565735
Change-Id: Id0a9a685536d5e18a3e42124a25ab08ff3a918f2
This commit is contained in:
Alessio Quaglino
2026-04-20 04:40:34 -07:00
committed by Copybara-Service
parent fa7b36d111
commit 508e581ba9
12 changed files with 455 additions and 90 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/engine/engine_core_smooth.c
+14 -16
View File
@@ -564,16 +564,13 @@ void mj_flex(const mjModel* m, mjData* d) {
// 0: vertices are the mesh vertices, 1: vertices are interpolated from nodal dofs
if (m->flex_interp[f] == 0) {
// centered: copy body position
if (m->flex_centered[f]) {
for (int i=vstart; i < vend; i++) {
for (int i=vstart; i < vend; i++) {
if (m->flex_centered[f] ||
(m->flex_vert[3*i+0] == 0 &&
m->flex_vert[3*i+1] == 0 &&
m->flex_vert[3*i+2] == 0)) {
mji_copy3(d->flexvert_xpos+3*i, d->xpos+3*m->flex_vertbodyid[i]);
}
}
// non-centered: map from local to global
else {
for (int i=vstart; i < vend; i++) {
} else {
mji_mulMatVec3(d->flexvert_xpos+3*i, d->xmat+9*m->flex_vertbodyid[i], m->flex_vert+3*i);
mji_addTo3(d->flexvert_xpos+3*i, d->xpos+3*m->flex_vertbodyid[i]);
}
@@ -585,13 +582,14 @@ void mj_flex(const mjModel* m, mjData* d) {
int nodenum = nend - nstart;
mj_markStack(d);
mjtNum* nodexpos = mjSTACKALLOC(d, 3*nodenum, mjtNum);
if (m->flex_centered[f]) {
for (int i=nstart; i < nend; i++) {
mji_copy3(nodexpos + 3*(i-nstart), d->xpos + 3*m->flex_nodebodyid[i]);
}
} else {
for (int i=nstart; i < nend; i++) {
int j = i - nstart;
for (int i=nstart; i < nend; i++) {
int j = i - nstart;
if (m->flex_centered[f] ||
(m->flex_node[3*i+0] == 0 &&
m->flex_node[3*i+1] == 0 &&
m->flex_node[3*i+2] == 0)) {
mji_copy3(nodexpos + 3*j, d->xpos + 3*m->flex_nodebodyid[i]);
} else {
mji_mulMatVec3(nodexpos + 3*j, d->xmat + 9*m->flex_nodebodyid[i], m->flex_node + 3*i);
mji_addTo3(nodexpos + 3*j, d->xpos + 3*m->flex_nodebodyid[i]);
}