And how do we link the vertices of the “3D file” (.egg for example) with the vertices of the tetra mesh? Just having the softbody simulation is not enough - People want to see a visual proxy of the softbody, something that get’s rendered, a triangle mesh. It’s good practice to have a visual mesh at high resolution (looks good) and a tetra mesh at low resolution (fast simulation).
.bullet file format a binary format to serialize different Bullet objects (and ONLY Bullet object). It is quite new, and nowhere stable. I have added code to save/load single Bullet shapes around r4/r5, and by r7 the code has been broken again. No idea why.
Anyway, .bullet is not the right way to go. On the long run we need something independent from any particular physics engine, like .egg or .dae