How to attach multiple rod ends to arbitrary local positions on a single rigid body?

[Rio511]

Hello,
I am currently trying to build a simulation model where multiple soft rods are fixed at their base ends, while their free ends are rigidly attached to different positions on a single rigid body. External forces and torques will be applied directly to this rigid body, and I aim to observe the overall deformation behavior of the entire system through this method.
I’ve noticed that the current joint and connection implementation in the codebase does not seem to support attaching a soft rod to a specific local position on a rigid body (other than its center node/index 0).
Could you please advise any alternative implementation scheme or workaround to achieve this function? I am quite new to this community, and I apologize in advance if I have overlooked any existing built-in methods that can already realize this requirement.

[Rio511]

The physical model would be like this:

[sy-cui]

@Rio511 The rigid body currently implemented in PyElastica does not have extensive functionalities outside of basic kinematics. We provide the framework for integrating rigid bodies, but you need to provide your own geometry and kinematics for the rigid bodies that you want to use. For example, you likely need to implement your own rigid body class, prescribe the center of mass, points where the rods can be attached, and write your own functions how forces imposed at these points translate to the rigid body dynamics.

@Ali-7800 Do we have simple examples for something like this?

[Ali-7800]

@Rio511 @sy-cui We have the connection you are thinking of in elastica.experimental. You could try to use that.