How to properly generate .vtk file from .obj file?

[ProgrammingElite]

I want to load deformable object in PyBullet with function "loadSoftBody". I know that PyBullet offers example object file "torus.obj" and "torus.vtk". It works well. However, when I try to generate .vtk file by myself from .obj with the following steps, PyBullet crashes down:

1. open .obj file in Blender in Windows and export .stl file
2. generate .msh file in TetWild (https://github.com/Yixin-Hu/TetWild) in Ubuntu with command in terminal: $ ./TetWild --input torus.stl --output torus.msh
3. open .msh file in Gmsh in Windows and export .vtk file
4. run the following Python script:

   
   import pybullet as p
   from time import sleep
   import pybullet_data

physicsClient = p.connect(p.GUI)

p.setAdditionalSearchPath(pybullet_data.getDataPath())

p.resetSimulation(p.RESET_USE_DEFORMABLE_WORLD) p.setGravity(0, 0, -10)

planeId = p.loadURDF("plane.urdf", [0,0,0])

original .vtk file ------- success

softBodyId1 = p.loadSoftBody("original files/torus.vtk", basePosition = [0,0,5])

generated .vtk file ------- fail

softBodyId2 = p.loadSoftBody("generated files/torus.vtk", basePosition = [0,0,5])

p.setRealTimeSimulation(0)

while p.isConnected(): p.stepSimulation()

Then PyBullet crashes down.

pybullet build time: May 20 2022 19:44:17 startThreads creating 1 threads. starting thread 0 started thread 0 argc=2 argv[0] = --unused argv[1] = --start_demo_name=Physics Server ExampleBrowserThreadFunc started X11 functions dynamically loaded using dlopen/dlsym OK! X11 functions dynamically loaded using dlopen/dlsym OK! Creating context Created GL 3.3 context Direct GLX rendering context obtained Making context current GL_VENDOR=VMware, Inc. GL_RENDERER=SVGA3D; build: RELEASE; LLVM; GL_VERSION=4.1 (Core Profile) Mesa 21.2.6 GL_SHADING_LANGUAGE_VERSION=4.10 pthread_getconcurrency()=0 Version = 4.1 (Core Profile) Mesa 21.2.6 Vendor = VMware, Inc. Renderer = SVGA3D; build: RELEASE; LLVM; b3Printf: Selected demo: Physics Server startThreads creating 1 threads. starting thread 0 started thread 0 MotionThreadFunc thread started ven = VMware, Inc. ven = VMware, Inc. Segmentation fault (core dumped)

All the files are attached in the [files.zip](https://pybullet.org/Bullet/phpBB3/download/file.php?id=1966) 
Folder "original files" are files provided by PyBullet git repository. Folder "generated files" are files generated by myself. I search for the solution online and issue #2726 but **still cannot solve this problem**.

[ProgrammingElite]

@erwincoumans

[renatyv]

All the files are attached in the [files.zip]

I generated .vtk file from yours and it works. Don't forget to check the "save all elements" mark and choose "ASCII" format when exporting .vtk file using GMSH.

[ProgrammingElite]

I try it on Windows PyBullet and it works! But when I try it on VMware Ubuntu 20.04 PyBullet, the problem occurs. Why?

[lidaken]

The process I translate to vtk is same to you, and I got error in Ubuntu PyBullet: malloc():memory corruption. Do you get the reason now?

[ProgrammingElite]

您的邮件已收到，谢谢！

[lucky3362]

please tell me how to fix this problem?

[ProgrammingElite]

您的邮件已收到，谢谢！

[lucky3362]

I have found the answer. When you use tetwild on Linux and Gmsh on Windows, this will result in an error. Only when both are used on Linux can success.