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Add disc mesh generation to user_flexcomp.

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PiperOrigin-RevId: 611462985
Change-Id: I0fc195d8733172f5f4347b04b5de0edfdd12613d
This commit is contained in:
Alessio Quaglino
2024-02-29 07:23:46 -08:00
committed by Copybara-Service
parent f9c46e2abb
commit 8f1ea05bef
4 changed files with 112 additions and 10 deletions
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model/plugin/elasticity/pancake_flex.xml
+50
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@@ -0,0 +1,50 @@
<!-- Copyright 2024 DeepMind Technologies Limited
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<mujoco model="Pancake">
<include file="scene.xml"/>
<extension>
<plugin plugin="mujoco.elasticity.shell"/>
</extension>
<option timestep="0.001" solver="CG" tolerance="1e-6" integrator="implicitfast"/>
<size memory="10M"/>
<visual>
<map stiffness="100"/>
</visual>
<default>
<default class="wall">
<geom type="plane" size=".5 .5 .05"/>
</default>
</default>
<worldbody>
<flexcomp type="disc" count="9 9 1" spacing=".1 .1 .1" pos="0 0 .5"
radius=".01" mass=".5" name="plate" dim="2">
<contact condim="3" solref="0.01 1" solimp=".95 .99 .0001"/>
<edge equality="true" damping="10"/>
<plugin plugin="mujoco.elasticity.shell">
<config key="poisson" value="0"/>
<config key="thickness" value="8e-3"/>
<!--Units are in Pa (SI)-->
<config key="young" value="3e5"/>
</plugin>
</flexcomp>
</worldbody>
</mujoco>
src/user/user_flexcomp.cc
+57 -10
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@@ -84,6 +84,7 @@ mjCFlexcomp::mjCFlexcomp(void) {
// make flexcomp object
bool mjCFlexcomp::Make(mjCModel* model, mjmBody* body, char* error, int error_sz) {
mjmFlex* dflex = def.spec.flex;
int dim = dflex->dim;
bool radial = (type==mjFCOMPTYPE_BOX ||
type==mjFCOMPTYPE_CYLINDER ||
type==mjFCOMPTYPE_ELLIPSOID);
@@ -96,9 +97,14 @@ bool mjCFlexcomp::Make(mjCModel* model, mjmBody* body, char* error, int error_sz
return comperr(error, "Parent body must have name", error_sz);
}
// check dim
if (dim<1 || dim>3) {
return comperr(error, "Invalid dim, must be between 1 and 3", error_sz);
}
// check counts
for (int i=0; i<3; i++) {
if (count[i]<1 || (radial && count[i]<2)) {
if (count[i]<1 || ((radial && count[i]<2) && dim==3)) {
return comperr(error, "Count too small", error_sz);
}
}
@@ -142,6 +148,11 @@ bool mjCFlexcomp::Make(mjCModel* model, mjmBody* body, char* error, int error_sz
res = MakeBox(error, error_sz);
break;
case mjFCOMPTYPE_SQUARE:
case mjFCOMPTYPE_DISC:
res = MakeSquare(error, error_sz);
break;
case mjFCOMPTYPE_MESH:
res = MakeMesh(model, error, error_sz);
break;
@@ -161,12 +172,6 @@ bool mjCFlexcomp::Make(mjCModel* model, mjmBody* body, char* error, int error_sz
return false;
}
// get dim and check
int dim = dflex->dim;
if (dim<1 || dim>3) {
return comperr(error, "Invalid dim, must be between 1 and 3", error_sz);
}
// force flatskin shading for box, cylinder and 3D grid
if (type==mjFCOMPTYPE_BOX || type==mjFCOMPTYPE_CYLINDER ||
(type==mjFCOMPTYPE_GRID && dim==3)) {
@@ -540,12 +545,15 @@ bool mjCFlexcomp::MakeGrid(char* error, int error_sz) {
// 2D
else if (dim==2) {
int quad2tri[2][3] = {{0, 1, 2}, {0, 2, 3}};
for (int ix=0; ix<count[0]; ix++) {
for (int iy=0; iy<count[1]; iy++) {
int quad2tri[2][3] = {{0, 1, 2}, {0, 2, 3}};
// add point
point.push_back(spacing[0]*(ix - 0.5*(count[0]-1)));
point.push_back(spacing[1]*(iy - 0.5*(count[1]-1)));
mjtNum pos[2] = {spacing[0]*(ix- 0.5*(count[0]-1)),
spacing[1]*(iy- 0.5*(count[1]-1))};
point.push_back(pos[0]);
point.push_back(pos[1]);
point.push_back(0);
// add texture coordinates, if not specified explicitly
@@ -554,6 +562,14 @@ bool mjCFlexcomp::MakeGrid(char* error, int error_sz) {
texcoord.push_back(iy/(mjtNum)mjMAX(count[1]-1, 1));
}
// flip triangles if radial projection is requested
if (((pos[0] < -mjEPS && pos[1] > -mjEPS) ||
(pos[0] > -mjEPS && pos[1] < -mjEPS)) &&
type == mjFCOMPTYPE_DISC) {
quad2tri[0][2] = 3;
quad2tri[1][0] = 1;
}
// add elements
if (ix<count[0]-1 && iy<count[1]-1) {
int vert[4] = {
@@ -695,6 +711,37 @@ void mjCFlexcomp::BoxProject(double* pos, int ix, int iy, int iz) {
// make 2d square or disc
bool mjCFlexcomp::MakeSquare(char* error, int error_sz) {
// set 2D
def.spec.flex->dim = 2;
// create square
if (!MakeGrid(error, error_sz)) {
return false;
}
// do projection
if (type==mjFCOMPTYPE_DISC) {
double size[2] = {
0.5*spacing[0]*(count[0]-1),
0.5*spacing[1]*(count[1]-1),
};
for (int i=0; i<point.size()/3; i++) {
mjtNum* pos = point.data() + i*3;
double L0 = mjMAX(mju_abs(pos[0]), mju_abs(pos[1]));
mjuu_normvec(pos, 2);
pos[0] *= size[0]*L0;
pos[1] *= size[1]*L0;
}
}
return true;
}
// make 3d box, ellipsoid or cylinder
bool mjCFlexcomp::MakeBox(char* error, int error_sz) {
double pos[3];
src/user/user_flexcomp.h
+3
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@@ -29,6 +29,8 @@ typedef enum _mjtFcompType {
mjFCOMPTYPE_BOX,
mjFCOMPTYPE_CYLINDER,
mjFCOMPTYPE_ELLIPSOID,
mjFCOMPTYPE_SQUARE,
mjFCOMPTYPE_DISC,
mjFCOMPTYPE_MESH,
mjFCOMPTYPE_GMSH,
mjFCOMPTYPE_DIRECT,
@@ -44,6 +46,7 @@ class mjCFlexcomp {
bool MakeGrid(char* error, int error_sz);
bool MakeBox(char* error, int error_sz);
bool MakeSquare(char* error, int error_sz);
bool MakeMesh(mjCModel* model, char* error, int error_sz);
bool MakeGMSH(mjCModel* model, char* error, int error_sz);
void LoadGMSH(mjCModel* model, mjResource* resource);
src/xml/xml_native_reader.cc
+2
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@@ -750,6 +750,8 @@ const mjMap fcomp_map[mjNFCOMPTYPES] = {
{"box", mjFCOMPTYPE_BOX},
{"cylinder", mjFCOMPTYPE_CYLINDER},
{"ellipsoid", mjFCOMPTYPE_ELLIPSOID},
{"square", mjFCOMPTYPE_SQUARE},
{"disc", mjFCOMPTYPE_DISC},
{"mesh", mjFCOMPTYPE_MESH},
{"gmsh", mjFCOMPTYPE_GMSH},
{"direct", mjFCOMPTYPE_DIRECT}