Allow malformed meshes for visualization purposes. Throw error only if the mesh is required for inertia computation.

PiperOrigin-RevId: 466421062
Change-Id: I947dbc107e481bd8c328b1a6430ab2e88bc82fd6

src/xml/xml_native_reader.cc

@@ -2284,7 +2284,7 @@ void mjXReader::Body(XMLElement* section, mjCBody* pbody) {
       if (pbody->id==0) {
         throw mjXError(elem, "World body cannot have inertia");
       }
-      pbody->explicit_inertial = true;
+      pbody->explicitinertial = true;
       ReadAttr(elem, "pos", 3, pbody->ipos, text, true);
       ReadAttr(elem, "quat", 4, pbody->iquat, text);
       ReadAttr(elem, "mass", 1, &pbody->mass, text, true);

src/xml/xml_native_writer.cc

@@ -1178,7 +1178,7 @@ void mjXWriter::Body(XMLElement* elem, mjCBody* body) {
     WriteVector(elem, "user", body->userdata);
 
     // write inertial
-    if (body->explicit_inertial &&
+    if (body->explicitinertial &&
         model->inertiafromgeom!=mjINERTIAFROMGEOM_TRUE) {
       XMLElement* inertial = InsertEnd(elem, "inertial");
       WriteAttr(inertial, "pos", 3, body->locipos);

src/xml/xml_urdf.cc

@@ -207,7 +207,7 @@ void mjXURDF::Body(XMLElement* body_elem) {
 
   // inertial element: copy into alternative body frame
   if ((elem = FindSubElem(body_elem, "inertial"))) {
-    pbody->explicit_inertial = true;
+    pbody->explicitinertial = true;
     // origin- relative to joint frame for now
     Origin(elem, pbody->ipos, pbody->iquat);