Physics Engineer Yushan Han goes over the process of setting up a Chaos Flesh simulation, using a provided Emil muscle asset and detailing the new features and workflow for 5.5 using Dataflow. The Chaos Flesh system provides high-quality, real-time simulation of deformable (soft) bodies in Unreal Engine, and this example will take the user through initial flesh setup through caching a final simulated result.
https://dev.epicgames.com/community/learning/tutorials/W4mV/unreal-engine-chaos-flesh-muscle-simulation-tutorial-5-5
During the Muscle Simulation section, after recording the Muscle sim, the skeleton moves but the muscles still stay in place as if they never simulated.
Hi, looks like the kinematic constraints are not updated correctly. You can check if you have any kinematic constraints under Kinematic attribute, Vertices group in the Collection SpreadSheet window. Also you can verify in Name Attribute, Transform group if you have the skeleton name matching the skeleton being set in Asset Details window. The former one should be the skeleton from the skeletal mesh that you used to create the muscle tetrahedral mesh.
I also encountered the same problem,the skeleton moves but the muscles still stay in place as if they never simulated.
I can’t reproduce the muscles not following for the two of you experiencing it. Very strange. From what I can tell from your movie, the graph and sim settings look correct. I’ve tried with both animations, lift weights and ROM, can you swap out to the ROM and try that?
Also, as Yushan mentioned, check the spreadsheet to make sure the ‘Kinematic’ vertices are ‘true’.
Check to see if your Chaos Cache Collection is being written to. It should show up with an asterisk in the content editor.
I experienced this too and the way I fixed it was to keep going back and forth between the black and white paint map, inverting the surface and painting to make sure I’m capturing the surface. By default the "Strength’ on the paint tool is set to 0.5. Try bumping to 1.0 and paint over the areas where you are getting spikes.
You may actually see very small values on the ‘InnerFat’ vertices in the spreadsheet, and I think this may be contributing to the spikes. So paint/repaint as I mentioned above to clean up those values.
It can be a bit tedious, and we realize the painting tool in general needs a bit of love and will address that in the future.
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Thank you, I will try to repaint then, to see if it works better
Hello there, I am trying to make a GeometryCache using the GenerateGeometryCache button, but in the Output Log it says this:
SkeletalMeshAsset and FleshAsset have different vertex positions. Check if the assets have the same vertex order.
I am following the muscle tutorial from Epic Games (using their project examples) step by step, but I am feeling a bit lost. Does anyone know how to fix it?
Chaos Flesh Muscle Simulation 5.5
After the simulation is complete, the surface projection of the skeletal mesh is strange. I tried increasing and decreasing the property values of other binding nodes, but it still doesn’t work. How can I fix this?
Hi,
The GenerateSurfaceBindings node has a known issue of binding render mesh vertices to suboptimal surface triangles. This issue has been fixed for the 5.6 release. For the current version you can try reducing the number of iterations used in this node.