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Fix Mesh PhysicsCollisionAPI by accounting for how it's referenced/instanced.

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Because we introduce an additional parent scope when referencing a `Mesh` prim (required for instancing), we need to create an `over` prim that allows to actually operate on the to-be-referenced Mesh.

PiperOrigin-RevId: 753941355
Change-Id: I829be9e82fe650802afcbc46f4b2f4c81eb53bd1
This commit is contained in:
Robin Alazard
2025-05-02 03:46:34 -07:00
committed by Copybara-Service
parent 6c319310b8
commit 02656532c2
2 changed files with 45 additions and 5 deletions
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src/experimental/usd/plugins/mjcf/mujoco_to_usd.cc
+12 -4
View File
@@ -66,7 +66,6 @@ using TfStaticData = pxr::TfStaticData<T>;
// clang-format off
TF_DEFINE_PRIVATE_TOKENS(kTokens,
// Xform ops
((body, "Body"))
((body_name, "mujoco:body_name"))
((geom, "Geom"))
@@ -89,7 +88,8 @@ TF_DEFINE_PRIVATE_TOKENS(kTokens,
((outputsRgb, "outputs:rgb"))
((inputsMetallic, "inputs:metallic"))
(repeat)
);
((sourceMesh, pxr::UsdGeomTokens->Mesh))
);
// Using to satisfy TF_REGISTRY_FUNCTION macro below and avoid operating in PXR_NS.
using pxr::TfEnum;
@@ -330,7 +330,7 @@ class ModelWriter {
pxr::SdfPath subcomponent_path =
CreatePrimSpec(data_, parent_path, name, pxr::UsdGeomTokens->Xform);
pxr::SdfPath mesh_path =
CreatePrimSpec(data_, subcomponent_path, pxr::UsdGeomTokens->Mesh,
CreatePrimSpec(data_, subcomponent_path, kTokens->sourceMesh,
pxr::UsdGeomTokens->Mesh);
mesh_paths_[*mesh->name] = subcomponent_path;
@@ -600,7 +600,15 @@ class ModelWriter {
// Reference the mesh asset written in WriteMeshes.
AddPrimReference(data_, subcomponent_path, mesh_paths_[*geom->meshname]);
return subcomponent_path;
// We want to use instancing with meshes, and it requires creating a parent
// scope to be referenced, with the Mesh prim as a child.
// To be able to actually manipulate the Mesh prim, we need to create and
// return the corresponding `over` prim as a child of the referencing prim.
pxr::SdfPath over_mesh_path =
CreatePrimSpec(data_, subcomponent_path, kTokens->sourceMesh,
pxr::UsdGeomTokens->Mesh, pxr::SdfSpecifierOver);
return over_mesh_path;
}
pxr::SdfPath WriteSiteGeom(const mjsSite *site,
test/experimental/usd/plugins/mjcf/mjcf_file_format_test.cc
+33 -1
View File
@@ -612,6 +612,9 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsRigidBody) {
TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsColliders) {
static constexpr char kXml[] = R"(
<mujoco model="test">
<asset>
<mesh name="tetrahedron" vertex="0 0 0 1 0 0 0 1 0 0 0 1"/>
</asset>
<worldbody>
<geom name="ground" type="plane" size="5 5 0.1"
contype="1" conaffinity="1"/>
@@ -636,6 +639,11 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsColliders) {
<geom name="body_2_nocol" type="sphere" size="1"
contype="0" conaffinity="0"/>
</body>
<body name="body_3" pos="0 3 3">
<joint type="free"/>
<geom name="body_3_col" type="mesh" mesh="tetrahedron"
contype="1" conaffinity="1"/>
</body>
</worldbody>
</mujoco>
)";
@@ -655,7 +663,7 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsColliders) {
// body_0/body_0 [rigidbody]
// body_0/body_0/body_0_col [collider]
//
// body_0/body_0_0 [rigidbody] <-- Note: USD reparents nested rigid bodies
// body_0/body_0_0 [rigidbody] <-- USD reparents nested rigid bodies
// body_0/body_0/body_0_0/body_0_0_col [collider]
//
// body_1/body_1 [rigidbody]
@@ -664,6 +672,10 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsColliders) {
//
// body_2/body_2 [rigidbody]
// body_2/body_2/body_2_nocol []
//
// body_3/body_3 [rigidbody]
// body_3/body_3/body_3_col [] <-- Intermediate prim for mesh instancing
// body_3/body_3/body_3_col/Mesh [collider]
// ground [collider] (Static collider)
EXPECT_PRIM_VALID(stage, "/test/ground");
@@ -728,6 +740,26 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsColliders) {
pxr::UsdPhysicsRigidBodyAPI);
EXPECT_PRIM_API_NOT_APPLIED(stage, "/test/body_2/body_2/body_2_nocol",
pxr::UsdPhysicsCollisionAPI);
// body_3/body_3 [rigidbody]
EXPECT_PRIM_VALID(stage, "/test/body_3/body_3");
EXPECT_PRIM_API_APPLIED(stage, "/test/body_3/body_3",
pxr::UsdPhysicsRigidBodyAPI);
EXPECT_PRIM_API_NOT_APPLIED(stage, "/test/body_3/body_3",
pxr::UsdPhysicsCollisionAPI);
// body_3/body_3/body_3_col [] (Intermediate prim for mesh instancing)
EXPECT_PRIM_VALID(stage, "/test/body_3/body_3/body_3_col");
EXPECT_PRIM_API_NOT_APPLIED(stage, "/test/body_3/body_3/body_3_col",
pxr::UsdPhysicsRigidBodyAPI);
EXPECT_PRIM_API_NOT_APPLIED(stage, "/test/body_3/body_3/body_3_col",
pxr::UsdPhysicsCollisionAPI);
// body_3/body_3/body_3_col/Mesh [collider]
EXPECT_PRIM_VALID(stage, "/test/body_3/body_3/body_3_col/Mesh");
EXPECT_PRIM_API_NOT_APPLIED(
stage, "/test/body_3/body_3/body_3_col/Mesh",
pxr::UsdPhysicsRigidBodyAPI);
EXPECT_PRIM_API_APPLIED(stage, "/test/body_3/body_3/body_3_col/Mesh",
pxr::UsdPhysicsCollisionAPI);
}
} // namespace