Blender simulation of inextensible cloth using Bullet?

[Jan Bender]

Hi Erwin,

I found the following Blender feature video:

http://www.blender.org/features-gallery ... softbodies

I suppose this is simulated using the Bullet engine. In this video the option "stiff quads" is enabled and the title of this part is "Diagonal springs". Do you use a quad mesh with springs on the diagonal? I am just implementing something similar. So what are your experiences with it.

Thanks,

Jan

[Erwin Coumans]

Blender has two cloth systems, and only the built-in game engine uses currently Bullet. So this video is not using Bullet.

Bullet has the option to create diagonal links, when creating a cloth patch using 'btSoftBodyHelpers::CreatePatch'. There are position and velocity (impulse) solvers for links, not using spring forces.

Why would you use spring forces? Can't you just solve those diagonal links using position/velocity based approach like the rest of the cloth?
Thanks,
Erwin