source/blender/io/usd/intern/usd_reader_skeleton.cc

@@ -14,16 +14,10 @@
 #include "DNA_armature_types.h"
 #include "DNA_object_types.h"
 
-#include "ED_armature.h"
-
 #include "MEM_guardedalloc.h"
 
 #include "WM_api.h"
 
-#include <pxr/pxr.h>
-#include <pxr/usd/usdSkel/cache.h>
-#include <pxr/usd/usdSkel/skeletonQuery.h>
-
 #include <iostream>
 
 namespace blender::io::usd {
@@ -47,208 +41,7 @@ void USDSkeletonReader::read_object_data(Main *bmain, const double motionSampleT
     return;
   }
 
-  pxr::UsdSkelCache skel_cache;
-  pxr::UsdSkelSkeletonQuery skel_query = skel_cache.GetSkelQuery(skel_);
-
-  if (!skel_query.IsValid()) {
-    std::cout << "WARNING: couldn't query skeleton " << skel_.GetPath() << std::endl;
-    return;
-  }
-
-  const pxr::UsdSkelTopology &skel_topology = skel_query.GetTopology();
-
-  pxr::VtTokenArray joint_order = skel_query.GetJointOrder();
-
-  if (joint_order.size() != skel_topology.size()) {
-    std::cout << "WARNING: skel topology and joint order size mismatch\n";
-    return;
-  }
-
-  bArmature *arm = static_cast<bArmature *>(object_->data);
-
-  ED_armature_to_edit(arm);
-
-  /* The bones we create, stored in the skeleton's joint order. */
-  std::vector<EditBone *> edit_bones;
-
-  size_t num_joints = skel_topology.GetNumJoints();
-
-  /* Keep track of the bones we create for each joint. */
-  std::map<pxr::TfToken, std::string> joint_to_bone_map;
-
-  /* Create the bones. */
-  for (const pxr::TfToken &joint : joint_order) {
-    std::string name = pxr::SdfPath(joint).GetName();
-    EditBone * bone = ED_armature_ebone_add(arm, name.c_str());
-    if (!bone) {
-      std::cout << "WARNING: couldn't add bone for joint " << joint << std::endl;
-      edit_bones.push_back(nullptr);
-      continue;
-    }
-    joint_to_bone_map.insert(std::make_pair(joint, bone->name));
-    edit_bones.push_back(bone);
-  }
-
-  /* Sanity check: we should have created a bone for each joint. */
-
-  if (edit_bones.size() != num_joints) {
-    std::cout << "WARNING: mismatch in bone and joint counts for skeleton " << skel_.GetPath() << std::endl;
-    return;
-  }
-
-  /* Record the child bone indices per parent bone. */
-  std::vector<std::vector<int>> child_bones(num_joints);
-
-  /* Set bone parenting. */
-  for (size_t i = 0; i < num_joints; ++i) {
-    int parent_idx = skel_topology.GetParent(i);
-    if (parent_idx < 0) {
-      continue;
-    }
-    if (parent_idx >= edit_bones.size()) {
-      std::cout << "WARNING: out of bounds parent index for bone " << pxr::SdfPath(joint_order[i])
-                << " for skeleton " << skel_.GetPath() << std::endl;
-      continue;
-    }
-
-    child_bones[parent_idx].push_back(i);
-    if (edit_bones[i] && edit_bones[parent_idx]) {
-      edit_bones[i]->parent = edit_bones[parent_idx];
-    }
-  }
-
-  /* Joint bind transforms. */
-  pxr::VtMatrix4dArray bind_xforms;
-  if (!skel_query.GetJointWorldBindTransforms(&bind_xforms)) {
-    std::cout << "WARNING: couldn't get world bind transforms for skeleton "
-              << skel_query.GetSkeleton().GetPrim().GetPath() << std::endl;
-    return;
-  }
-
-  if (bind_xforms.size() != num_joints) {
-    std::cout << "WARNING: mismatch in local space rest xforms and joint counts for skeleton " << skel_.GetPath() << std::endl;
-    return;
-  }
-
-  /* Check if any bone natrices have negative determinants,
-   * indicating negative scales, possibly due to mirroring
-   * operations.  Such matrices can't be propery converted
-   * to Blender's axis/roll bone representation (see
-   * https://developer.blender.org/T82930).  If we detect
-   * such matrices, we will flag an error and won't try
-   * to import the animation, since the rotations would
-   * be incorrect in such cases.  Unfortunately, the Pixar
-   * UsdSkel examples of the "HumanFemale" suffer from
-   * this issue. */
-  bool negative_determinant = false;
-
-  /* Set bone rest transforms. */
-  for (size_t i = 0; i < num_joints; ++i) {
-    EditBone *ebone = edit_bones[i];
-
-    if (!ebone) {
-      continue;
-    }
-
-    pxr::GfMatrix4f mat(bind_xforms[i]);
-
-    float mat4[4][4];
-    mat.Get(mat4);
-
-    pxr::GfVec3f head(0.0f, 0.0f, 0.0f);
-    pxr::GfVec3f tail(0.0f, 1.0f, 0.0f);
-
-    copy_v3_v3(ebone->head, head.data());
-    copy_v3_v3(ebone->tail, tail.data());
-
-    ED_armature_ebone_from_mat4(ebone, mat4);
-
-    if (mat.GetDeterminant() < 0.0) {
-      negative_determinant = true;
-    }
-  }
-
-  bool valid_skeleton = true;
-  if (negative_determinant) {
-    valid_skeleton = false;
-    WM_reportf(RPT_WARNING,
-               "USD Skeleton Import: bone matrices with negative determinants detected in prim %s."
-               "Such matrices may indicate negative scales, possibly due to mirroring operations, "
-               "and can't currently be converted to Blender's bone representation.  "
-               "The skeletal animation won't be imported", prim_.GetPath().GetAsString().c_str());
-  }
-
-  /* Scale bones to account for separation between parents and
-   * children, so that the bone size is in proportion with the
-   * overall skeleton hierarchy.  USD skeletons are composed of
-   * joints which we imperfectly represent as bones. */
-
-  float avg_len_scale = 0;
-  for (size_t i = 0; i < num_joints; ++i) {
-
-    /* If the bone has any children, scale its length
-     * by the distance between this bone's head
-     * and the average head location of its children. */
-
-    if (child_bones[i].empty()) {
-      continue;
-    }
-
-    EditBone *parent = edit_bones[i];
-    if (!parent) {
-      continue;
-    }
-
-    pxr::GfVec3f avg_child_head(0);
-    for (int j : child_bones[i]) {
-      EditBone *child = edit_bones[j];
-      if (!child) {
-        continue;
-      }
-      pxr::GfVec3f child_head(child->head);
-      avg_child_head += child_head;
-    }
-
-    avg_child_head /= child_bones[i].size();
-
-    pxr::GfVec3f parent_head(parent->head);
-    pxr::GfVec3f parent_tail(parent->tail);
-
-    float new_len = (avg_child_head - parent_head).GetLength();
-
-    /* Be sure not to scale by zero. */
-    if (new_len > .00001) {
-      parent_tail = parent_head + (parent_tail - parent_head).GetNormalized() * new_len;
-      copy_v3_v3(parent->tail, parent_tail.data());
-      avg_len_scale += new_len;
-    }
-  }
-
-  /* Scale terminal bones by the average length scale. */
-  avg_len_scale /= num_joints;
-
-  if (avg_len_scale > .00001) {
-    for (size_t i = 0; i < num_joints; ++i) {
-      if (!child_bones[i].empty()) {
-        continue;
-      }
-      EditBone *bone = edit_bones[i];
-      if (!bone) {
-        continue;
-      }
-      pxr::GfVec3f head(bone->head);
-      pxr::GfVec3f tail(bone->tail);
-      tail = head + (tail - head).GetNormalized() * avg_len_scale;
-      copy_v3_v3(bone->tail, tail.data());
-    }
-  }
-
-  ED_armature_from_edit(bmain, arm);
-  ED_armature_edit_free(arm);
-
-  if (valid_skeleton) {
-    create_skeleton_curves(bmain, object_, skel_query, joint_to_bone_map);
-  }
+  import_skeleton(bmain, object_, skel_);
 
   USDXformReader::read_object_data(bmain, motionSampleTime);
 }

source/blender/io/usd/intern/usd_skel_convert.cc

@@ -9,6 +9,8 @@
 #include <pxr/usd/usdSkel/animation.h>
 #include <pxr/usd/usdSkel/blendShape.h>
 #include <pxr/usd/usdSkel/bindingAPI.h>
+#include <pxr/usd/usdSkel/cache.h>
+#include <pxr/usd/usdSkel/skeletonQuery.h>
 #include <pxr/usd/usdSkel/utils.h>
 
 #include "DNA_anim_types.h"
@@ -33,9 +35,12 @@
 
 #include "BLI_math_vector.h"
 
+#include "ED_armature.h"
 #include "ED_keyframing.h"
 #include "ED_mesh.h"
 
+#include "WM_api.h"
+
 #include <string>
 #include <vector>
 
@@ -313,6 +318,215 @@ void import_blendshapes(Main *bmain, Object *obj, pxr::UsdPrim prim)
 
 }
 
+void import_skeleton(Main *bmain, Object *obj, const pxr::UsdSkelSkeleton &skel)
+{
+  pxr::UsdSkelCache skel_cache;
+  pxr::UsdSkelSkeletonQuery skel_query = skel_cache.GetSkelQuery(skel);
+
+  if (!skel_query.IsValid()) {
+    std::cout << "WARNING: couldn't query skeleton " << skel.GetPath() << std::endl;
+    return;
+  }
+
+  const pxr::UsdSkelTopology &skel_topology = skel_query.GetTopology();
+
+  pxr::VtTokenArray joint_order = skel_query.GetJointOrder();
+
+  if (joint_order.size() != skel_topology.size()) {
+    std::cout << "WARNING: skel topology and joint order size mismatch\n";
+    return;
+  }
+
+  bArmature *arm = static_cast<bArmature *>(obj->data);
+
+  ED_armature_to_edit(arm);
+
+  /* The bones we create, stored in the skeleton's joint order. */
+  std::vector<EditBone *> edit_bones;
+
+  size_t num_joints = skel_topology.GetNumJoints();
+
+  /* Keep track of the bones we create for each joint. */
+  std::map<pxr::TfToken, std::string> joint_to_bone_map;
+
+  /* Create the bones. */
+  for (const pxr::TfToken &joint : joint_order) {
+    std::string name = pxr::SdfPath(joint).GetName();
+    EditBone *bone = ED_armature_ebone_add(arm, name.c_str());
+    if (!bone) {
+      std::cout << "WARNING: couldn't add bone for joint " << joint << std::endl;
+      edit_bones.push_back(nullptr);
+      continue;
+    }
+    joint_to_bone_map.insert(std::make_pair(joint, bone->name));
+    edit_bones.push_back(bone);
+  }
+
+  /* Sanity check: we should have created a bone for each joint. */
+
+  if (edit_bones.size() != num_joints) {
+    std::cout << "WARNING: mismatch in bone and joint counts for skeleton " << skel.GetPath()
+              << std::endl;
+    return;
+  }
+
+  /* Record the child bone indices per parent bone. */
+  std::vector<std::vector<int>> child_bones(num_joints);
+
+  /* Set bone parenting. */
+  for (size_t i = 0; i < num_joints; ++i) {
+    int parent_idx = skel_topology.GetParent(i);
+    if (parent_idx < 0) {
+      continue;
+    }
+    if (parent_idx >= edit_bones.size()) {
+      std::cout << "WARNING: out of bounds parent index for bone " << pxr::SdfPath(joint_order[i])
+                << " for skeleton " << skel.GetPath() << std::endl;
+      continue;
+    }
+
+    child_bones[parent_idx].push_back(i);
+    if (edit_bones[i] && edit_bones[parent_idx]) {
+      edit_bones[i]->parent = edit_bones[parent_idx];
+    }
+  }
+
+  /* Joint bind transforms. */
+  pxr::VtMatrix4dArray bind_xforms;
+  if (!skel_query.GetJointWorldBindTransforms(&bind_xforms)) {
+    std::cout << "WARNING: couldn't get world bind transforms for skeleton "
+              << skel_query.GetSkeleton().GetPrim().GetPath() << std::endl;
+    return;
+  }
+
+  if (bind_xforms.size() != num_joints) {
+    std::cout << "WARNING: mismatch in local space rest xforms and joint counts for skeleton "
+              << skel.GetPath() << std::endl;
+    return;
+  }
+
+  /* Check if any bone natrices have negative determinants,
+   * indicating negative scales, possibly due to mirroring
+   * operations.  Such matrices can't be propery converted
+   * to Blender's axis/roll bone representation (see
+   * https://developer.blender.org/T82930).  If we detect
+   * such matrices, we will flag an error and won't try
+   * to import the animation, since the rotations would
+   * be incorrect in such cases.  Unfortunately, the Pixar
+   * UsdSkel examples of the "HumanFemale" suffer from
+   * this issue. */
+  bool negative_determinant = false;
+
+  /* Set bone rest transforms. */
+  for (size_t i = 0; i < num_joints; ++i) {
+    EditBone *ebone = edit_bones[i];
+
+    if (!ebone) {
+      continue;
+    }
+
+    pxr::GfMatrix4f mat(bind_xforms[i]);
+
+    float mat4[4][4];
+    mat.Get(mat4);
+
+    pxr::GfVec3f head(0.0f, 0.0f, 0.0f);
+    pxr::GfVec3f tail(0.0f, 1.0f, 0.0f);
+
+    copy_v3_v3(ebone->head, head.data());
+    copy_v3_v3(ebone->tail, tail.data());
+
+    ED_armature_ebone_from_mat4(ebone, mat4);
+
+    if (mat.GetDeterminant() < 0.0) {
+      negative_determinant = true;
+    }
+  }
+
+  bool valid_skeleton = true;
+  if (negative_determinant) {
+    valid_skeleton = false;
+    WM_reportf(RPT_WARNING,
+               "USD Skeleton Import: bone matrices with negative determinants detected in prim %s."
+               "Such matrices may indicate negative scales, possibly due to mirroring operations, "
+               "and can't currently be converted to Blender's bone representation.  "
+               "The skeletal animation won't be imported",
+               skel.GetPath().GetAsString().c_str());
+  }
+
+  /* Scale bones to account for separation between parents and
+   * children, so that the bone size is in proportion with the
+   * overall skeleton hierarchy.  USD skeletons are composed of
+   * joints which we imperfectly represent as bones. */
+
+  float avg_len_scale = 0;
+  for (size_t i = 0; i < num_joints; ++i) {
+
+    /* If the bone has any children, scale its length
+     * by the distance between this bone's head
+     * and the average head location of its children. */
+
+    if (child_bones[i].empty()) {
+      continue;
+    }
+
+    EditBone *parent = edit_bones[i];
+    if (!parent) {
+      continue;
+    }
+
+    pxr::GfVec3f avg_child_head(0);
+    for (int j : child_bones[i]) {
+      EditBone *child = edit_bones[j];
+      if (!child) {
+        continue;
+      }
+      pxr::GfVec3f child_head(child->head);
+      avg_child_head += child_head;
+    }
+
+    avg_child_head /= child_bones[i].size();
+
+    pxr::GfVec3f parent_head(parent->head);
+    pxr::GfVec3f parent_tail(parent->tail);
+
+    float new_len = (avg_child_head - parent_head).GetLength();
+
+    /* Be sure not to scale by zero. */
+    if (new_len > .00001) {
+      parent_tail = parent_head + (parent_tail - parent_head).GetNormalized() * new_len;
+      copy_v3_v3(parent->tail, parent_tail.data());
+      avg_len_scale += new_len;
+    }
+  }
+
+  /* Scale terminal bones by the average length scale. */
+  avg_len_scale /= num_joints;
+
+  if (avg_len_scale > .00001) {
+    for (size_t i = 0; i < num_joints; ++i) {
+      if (!child_bones[i].empty()) {
+        continue;
+      }
+      EditBone *bone = edit_bones[i];
+      if (!bone) {
+        continue;
+      }
+      pxr::GfVec3f head(bone->head);
+      pxr::GfVec3f tail(bone->tail);
+      tail = head + (tail - head).GetNormalized() * avg_len_scale;
+      copy_v3_v3(bone->tail, tail.data());
+    }
+  }
+
+  ED_armature_from_edit(bmain, arm);
+  ED_armature_edit_free(arm);
+
+  if (valid_skeleton) {
+    create_skeleton_curves(bmain, obj, skel_query, joint_to_bone_map);
+  }
+}
+
 void create_skeleton_curves(Main *bmain,
                             Object *obj,
                             const pxr::UsdSkelSkeletonQuery &skel_query,

source/blender/io/usd/intern/usd_skel_convert.h

@@ -19,6 +19,8 @@ struct ImportSettings;
 
 void import_blendshapes(Main *bmain, Object *shape_obj, pxr::UsdPrim prim);
 
+void import_skeleton(Main *bmain, Object *obj, const pxr::UsdSkelSkeleton &skel);
+
 void create_skeleton_curves(Main *bmain,
                             Object *obj,
                             const pxr::UsdSkelSkeletonQuery &skel_query,