Error: engine error: edge ordering is incoherent between flex and plugin / mujoco.elasticity.solid

[shunsei-t]

Hi,

I'm a student and I'm trying to use MuJoCo for elastic solid simulation.

I'm looking for some help with troubleshooting some errors.

Here is a model which explains my question:

minimal XML

```XML ```

minimal Python code

```Python import time import mujoco.viewer model = mujoco.MjModel.from_xml_path("assets/flex.xml") data = mujoco.MjData(model) n_steps = 5 with mujoco.viewer.launch_passive(model, data) as viewer: start = time.time() while True: step_start = time.time() for _ in range(n_steps): mujoco.mj_step(model, data) viewer.sync() time_until_next_step = model.opt.timestep - (time.time() - step_start) if time_until_next_step > 0: time.sleep(time_until_next_step) ```

obj file obj_files.zip

Here is a error message.

ValueError: Error: engine error: edge ordering is incoherent between flex and plugin

and I saw this issue. https://github.com/google-deepmind/mujoco/issues/1647