Softbody drifting when self collisions enabled !!!! Help!!

[winspear]

Whenever I enable the self collisions for soft bodies, they start drifting like crazy. Here are the collision flags used.

Code: Select all

psb->m_cfg.collisions = btSoftBody::fCollision::CL_SS+
		btSoftBody::fCollision::CL_RS + btSoftBody::fCollision::CL_SELF;

When I remove CL_SELF from the above line, the drifting stops.
Anyone know what I am doing wrong here.

Thanks

[winspear]

Not sure if there are other ways to fix this but I found that I can control the drifting by adjusting 2 factors.

1. Number of clusters (adjusting generate clusters). The drifting linearly increases with the number of clusters.
2. Position solver iterations (piterations). The drifting decreases linearly with increase in solver iterations.

BUT, you will have to find the sweet spot for both the above factors for your soft body simulation to run smoothly without artifacts.

Hope this helps others.

[Erwin Coumans]

The reason is collisions between closeby collision clusters. The self-collision support is very basic and doesn't deal properly with this case, so the only workaround is trying to fix it at soft body creation time.

Thanks,
Erwin