Compatibility of SofaCUDA with AttachConstraint and SurfacePressureConstraint from SoftRobots Plugin

[iman-adibnazari]

Hello,

I am trying to speedup simulations of a soft robot I'm working with (simplified version pictured below). The main approach I've been trying to take has been by integrating the SofaCUDA package where possible, but I seem to be running into some issues regarding constraints. I am trying to use some attach constraints between portions of the robot and I am getting errors that indicate that the CudaVec3 template might not be compatible with that component. I was wondering if there are going to be similar compatibility issues with the SurfacePressureConstraint from the SoftRobots plugin and if there are any recommended ways to navigate these issues.

The above is an image of the robot while its deformed without any CUDA components. There are two low-stiffness segments (each with two internal pressure driven chambers) and one coupling component between the two that is higher-stiffness.

The above shows how the air chambers are configured in the neutral configuration of the robot, the purple points show points that I would like to be connected via AttachConstraint components, and the red box indicates a region of points that I'm currently tracking.

I would greatly appreciate any insight or recommendations on how to speed up this simulation with SofaCUDA or any other tools as well. Thank you!

[alxbilger]

Indeed, AttachConstraint has not been implemented in SofaCUDA, hence it cannot have a CUDA template. You can try to use a IdentityMapping to apply AttachConstraint on the CPU. This way your object is represented as a GPU-based MechanicalObject using the CUDA template, and a CPU-based MechanicalObject using a Vec3 template. The IdentityMapping links them both. Note that this solution implies CPU-GPU copies, hence it is not the most efficient implementation. But today, I am not sure you have other choices.

[iman-adibnazari]

That sounds great. Thank you for the idea! I will try it out.