enable file caching, currently only for Wavefront .obj files. You can disable file caching using

pybullet.setPhysicsEngineParameter(enableFileCaching=0)
Allow VR camera tracking only using position tracking, no orientation tracking (use
pybullet.setVRCamera([posX,posY,posZ],trackObjectFlag=0 or pybullet.VR_CAMERA_TRACK_OBJECT_ORIENTATION)

examples/Importers/ImportMeshUtility/b3ImportMeshUtility.cpp

@@ -7,7 +7,7 @@
 #include "../../Utils/b3ResourcePath.h"
 #include "Bullet3Common/b3FileUtils.h"
 #include "../../ThirdPartyLibs/stb_image/stb_image.h"
-
+#include "../ImportObjDemo/LoadMeshFromObj.h"
 bool b3ImportMeshUtility::loadAndRegisterMeshFromFileInternal(const std::string& fileName, b3ImportMeshData& meshData)
 {
 	B3_PROFILE("loadAndRegisterMeshFromFileInternal");
@@ -28,7 +28,8 @@ bool b3ImportMeshUtility::loadAndRegisterMeshFromFileInternal(const std::string&
 		std::vector<tinyobj::shape_t> shapes;
 		{
 			B3_PROFILE("tinyobj::LoadObj");
-			std::string err = tinyobj::LoadObj(shapes, relativeFileName, pathPrefix);
+			std::string err = LoadFromCachedOrFromObj(shapes, relativeFileName, pathPrefix);
+			//std::string err = tinyobj::LoadObj(shapes, relativeFileName, pathPrefix);
 		}
 		
 		GLInstanceGraphicsShape* gfxShape = btgCreateGraphicsShapeFromWavefrontObj(shapes);

examples/Importers/ImportObjDemo/LoadMeshFromObj.cpp

@@ -1,11 +1,56 @@
 #include "LoadMeshFromObj.h"
-#include"../../ThirdPartyLibs/Wavefront/tiny_obj_loader.h"
+
 #include "../../OpenGLWindow/GLInstanceGraphicsShape.h"
 #include <stdio.h> //fopen
 #include "Bullet3Common/b3AlignedObjectArray.h"
 #include <string>
 #include <vector>
 #include "Wavefront2GLInstanceGraphicsShape.h"
+#include "Bullet3Common/b3HashMap.h"
+
+struct CachedObjResult
+{
+	std::string m_msg;
+	std::vector<tinyobj::shape_t> m_shapes;
+};
+
+static b3HashMap<b3HashString, CachedObjResult> gCachedObjResults;
+static int gEnableFileCaching = 1;
+
+void b3EnableFileCaching(int enable)
+{
+	gEnableFileCaching  = enable;
+	if (enable==0)
+	{
+		gCachedObjResults.clear();
+	}
+}
+
+
+std::string LoadFromCachedOrFromObj(
+    std::vector<tinyobj::shape_t>& shapes,   // [output]
+    const char* filename,
+    const char* mtl_basepath)
+{
+	CachedObjResult* resultPtr = gCachedObjResults[filename];
+	if (resultPtr)
+	{
+		const CachedObjResult& result = *resultPtr;
+		shapes = result.m_shapes;
+		return result.m_msg;
+	}
+
+	std::string err = tinyobj::LoadObj(shapes, filename, mtl_basepath);
+	CachedObjResult result;
+	result.m_msg = err;
+	result.m_shapes = shapes;
+	if (gEnableFileCaching)
+	{
+		gCachedObjResults.insert(filename,result);
+	}
+	return err;
+}
+
 
 GLInstanceGraphicsShape* LoadMeshFromObj(const char* relativeFileName, const char* materialPrefixPath)
 {
@@ -13,7 +58,7 @@ GLInstanceGraphicsShape* LoadMeshFromObj(const char* relativeFileName, const cha
 	std::vector<tinyobj::shape_t> shapes;
 	{
 		B3_PROFILE("tinyobj::LoadObj2");
-		std::string err = tinyobj::LoadObj(shapes, relativeFileName, materialPrefixPath);
+		std::string  err  = LoadFromCachedOrFromObj(shapes, relativeFileName, materialPrefixPath);
 	}
 
 	{

examples/Importers/ImportObjDemo/LoadMeshFromObj.h

@@ -4,6 +4,14 @@
 
 struct GLInstanceGraphicsShape;
 
+#include"../../ThirdPartyLibs/Wavefront/tiny_obj_loader.h"
+
+void b3EnableFileCaching(int enable);
+
+std::string LoadFromCachedOrFromObj(
+    std::vector<tinyobj::shape_t>& shapes,   // [output]
+    const char* filename,
+    const char* mtl_basepath);
 
 GLInstanceGraphicsShape* LoadMeshFromObj(const char* relativeFileName, const char* materialPrefixPath);
 

examples/Importers/ImportURDFDemo/BulletUrdfImporter.cpp

@@ -634,8 +634,15 @@ btCollisionShape* convertURDFToCollisionShape(const UrdfCollision* collision, co
 		case UrdfGeometry::FILE_OBJ:
 			if (collision->m_flags & URDF_FORCE_CONCAVE_TRIMESH)
 			{
-				
-				glmesh = LoadMeshFromObj(collision->m_geometry.m_meshFileName.c_str(), 0);
+				char relativeFileName[1024];
+				char pathPrefix[1024];
+				pathPrefix[0] = 0;
+				if (b3ResourcePath::findResourcePath(collision->m_geometry.m_meshFileName.c_str(), relativeFileName, 1024))
+				{
+
+					b3FileUtils::extractPath(relativeFileName, pathPrefix, 1024);
+				}
+				glmesh = LoadMeshFromObj(collision->m_geometry.m_meshFileName.c_str(), pathPrefix);
 			}
 			else
 			{