ValueError: Error: invalid sizes in MSH file 'newcube_volume.msh'

[federicopilot]

Good day. i am trying to simulate a soft-body in MuJoCo that i have produced with OpenSCAD. My ultimative goal is to create a more complex structure in OpenSCAD and the simulate it in MuJoCo. For testing purpose i am therefore trying to simulate a simple body from OpenSCAD in MuJoCo so that it exhibits flexibile propertes. First i have created an stl file of the object. Since I am using the flexcomp properties I have tried to transfer the file to a GMSH format using the GSMH software exporting it as an msh file (version 4.1 ASCII). I have created a Volume using Geometry->Elementary entities->Add->Volume. With my python Skript and the corresponding msh file i run into the following error: ValueError: XML Error: Error: All nodes must be in single block. I have tried a lot of different strategies and now I am running out of options and desperatley need help to find a possible solution. Thank you very much!

import mujoco as mj import numpy as np import os from mujoco.glfw import glfw

Define Simulation parameters sim_time = 5 #Simulation time in s xml_path = "stl_integraton2.xml"#Name of the full path for the XML file #Define initial Position print_camera_config = 1 # set to 1 to print camera config (useful for initializing view of the model) gmsh_file = "cubic_v4.1.msh"

MuJoCo model XML MODEL_XML = f"""

with open(xml_path, "w") as f: f.write(MODEL_XML) #...

msh file: $MeshFormat 4.1 0 8 $EndMeshFormat $Entities 0 0 1 2 1 0 0 0 5 5 5 0 0 1 0 0 0 5 5 5 0 1 1 2 0 0 0 5 5 5 0 1 1 $EndEntities $Nodes 3 8 1 8 2 1 1 8 1 2 3 4 5 6 7 8 0 5 5 0 0 5 0 5 0 0 5 5 5 0 0 0 0 5 0 0 0 0 0 0 0 5 5 0 0 0 5 0 0 0 0 0 5 0 0 0 3 1 0 0 3 2 0 0 $EndNodes $Elements 2 18 1 18 2 1 2 12 1 1 2 3 2 2 1 4 3 6 1 3 4 1 5 4 5 5 1 8 6 1 6 8 7 2 6 3 8 5 2 4 9 2 5 7 10 6 2 7 11 5 6 7 12 6 5 8 3 1 4 6 13 6 2 5 7 14 6 1 5 3 15 5 1 4 2 16 2 6 5 3 17 1 6 5 8 18 5 3 1 2 $EndElements

hello I had to re-open an issue as i haven't resolved an issue that was unexpectedly closed:

Thank you @mohammad200h, I followed your advice and was able to generate two files for the surface and volume msh. I Even checked the file in GMSH and saw that the Volume and Surface entities have been seperated which was good. Then i tried to run the binary and Ascii msh file for the Volume and got the following error message: ValueError: Error: invalid sizes in MSH file 'newcube_volume.msh'. So far I have tried creating simpler objects and I have tried to use different versions of GMSH file in format 4.1 and format 2.2 (ascii or binary) which i read in the Mujoco Dokumentation. Unfortunately nothing worked and i am getting the same error code. i would be very thankful if you could look into it again.

thank you very much!

here is the original object(i had to change the form slightly but it is very similar to the original object at the begining of the issue) $MeshFormat 4.1 0 8 $EndMeshFormat $Entities 0 0 1 1 1 0 0 0 4 8 3 0 0 1 0 0 0 4 8 3 0 1 1 $EndEntities $Nodes 2 8 1 8 2 1 1 8 1 2 3 4 5 6 7 8 0 8 3 0 0 4 0 3 0 0 4 8 3 0 0 0 0 3 0 0 0 0 0 0 0 4 8 0 0 0 4 0 0 0 0 0 8 0 0 0 3 1 0 0 $EndNodes $Elements 2 18 1 18 2 1 2 12 1 1 2 3 2 2 1 4 3 6 1 3 4 1 5 4 5 5 1 8 6 1 6 8 7 2 6 3 8 5 2 4 9 2 5 7 10 6 2 7 11 5 6 7 12 6 5 8 3 1 4 6 13 6 5 2 8 14 1 5 2 4 15 1 5 8 2 16 1 6 2 8 17 6 1 2 3 18 6 5 7 2 $EndElements

newcube_volume.msh $MeshFormat 4.1 0 8 $EndMeshFormat $Entities 0 0 0 1 1 0 0 0 4 8 3 0 0 $EndEntities $Nodes 1 8 1 8 3 1 0 8 1 2 3 4not 5 6 7 8 0 8 3 4 0 3 4 8 3 0 0 3 0 0 0 4 8 0 4 0 0 0 8 0 $EndNodes $Elements 1 6 1 6 3 1 4 6 1 6 5 2 8 2 1 5 2 4 3 1 5 8 2 4 1 6 2 8 5 6 1 2 3 6 6 5 7 2 $EndElements

newcube_surface.msh

$MeshFormat 4.1 0 8 $EndMeshFormat $Entities 0 0 1 0 1 0 0 0 4 8 3 0 0 $EndEntities $Nodes 1 8 1 8 2 1 1 8 1 2 3 4 5 6 7 8 0 8 3 0 0 4 0 3 0 0 4 8 3 0 0 0 0 3 0 0 0 0 0 0 0 4 8 0 0 0 4 0 0 0 0 0 8 0 0 0 $EndNodes $Elements 1 12 1 12 2 1 2 12 1 1 2 3 2 2 1 4 3 6 1 3 4 1 5 4 5 5 1 8 6 1 6 8 7 2 6 3 8 5 2 4 9 2 5 7 10 6 2 7 11 5 6 7 12 6 5 8 $EndElements here is a screenshot of the object:

here is my code that i am using only showing the most essential parts: `import mujoco as mj import numpy as np import os from mujoco.glfw import glfw

Define Simulation parameters

sim_time = 5 #Simulation time in s xml_path = "stl_integraton2.xml"#Name of the full path for the XML file

Define initial Position

print_camera_config = 1 # set to 1 to print camera config (useful for initializing view of the model) gmsh_file = "newcube_volume.msh"

MuJoCo model XML

MODEL_XML = f"""

"""`

[federicopilot]

newcube.msh: $MeshFormat 4.1 0 8 $EndMeshFormat $Entities 0 0 1 1 1 0 0 0 4 8 3 0 0 1 0 0 0 4 8 3 0 1 1 $EndEntities $Nodes 2 8 1 8 2 1 1 8 1 2 3 4 5 6 7 8 0 8 3 0 0 4 0 3 0 0 4 8 3 0 0 0 0 3 0 0 0 0 0 0 0 4 8 0 0 0 4 0 0 0 0 0 8 0 0 0 3 1 0 0 $EndNodes $Elements 2 18 1 18 2 1 2 12 1 1 2 3 2 2 1 4 3 6 1 3 4 1 5 4 5 5 1 8 6 1 6 8 7 2 6 3 8 5 2 4 9 2 5 7 10 6 2 7 11 5 6 7 12 6 5 8 3 1 4 6 13 6 5 2 8 14 1 5 2 4 15 1 5 8 2 16 1 6 2 8 17 6 1 2 3 18 6 5 7 2 $EndElements

newcube_volume.msh $MeshFormat 4.1 0 8 $EndMeshFormat $Entities 0 0 0 1 1 0 0 0 4 8 3 0 0 $EndEntities $Nodes 1 8 1 8 3 1 0 8 1 2 3 4not 5 6 7 8 0 8 3 4 0 3 4 8 3 0 0 3 0 0 0 4 8 0 4 0 0 0 8 0 $EndNodes $Elements 1 6 1 6 3 1 4 6 1 6 5 2 8 2 1 5 2 4 3 1 5 8 2 4 1 6 2 8 5 6 1 2 3 6 6 5 7 2 $EndElements

newcube_surface.msh $MeshFormat 4.1 0 8 $EndMeshFormat $Entities 0 0 1 0 1 0 0 0 4 8 3 0 0 $EndEntities $Nodes 1 8 1 8 2 1 1 8 1 2 3 4 5 6 7 8 0 8 3 0 0 4 0 3 0 0 4 8 3 0 0 0 0 3 0 0 0 0 0 0 0 4 8 0 0 0 4 0 0 0 0 0 8 0 0 0 $EndNodes $Elements 1 12 1 12 2 1 2 12 1 1 2 3 2 2 1 4 3 6 1 3 4 1 5 4 5 5 1 8 6 1 6 8 7 2 6 3 8 5 2 4 9 2 5 7 10 6 2 7 11 5 6 7 12 6 5 8 $EndElements

[mohammad200h]

The #1850 has been reopened. Please see the continued discussion there.