But the model is still soft, at when it collides with ground it falls apart.
I want it to bounce, just like bunny or torus in SoftDemo app.
And I don't want it to destroy.
There are a number of things you can do. Increase the bending constraint distance. For example, psb.generateBendingConstraints(5). Basically, that is the link traversal distance to which cross-links are attached. For large, high resolution models, you need a larger value for structural integrity. Second, try reducing the mass (setTotalMass...). The nodes might be too heavy for the links to support their weight. Finally, for closed meshes (like the bunny and torus), you can use internal pressure (via the kPR constant), pose matching and volume matching, which all - in various ways - attempt to preserve the structure of an object. However, for something like a hat, I'd recommend first trying the bending constraint distance and mass, then setPose. Pressure is good for more of an organic, wobbly balloon look/feel.
Soft bodies can be a bit tricky to sort out. Attached is a rough list of bits of info I've found about the various settings (mostly in softBody.m_cfg and softBody.m_materials), in case it helps.
EDIT: I should probably note that I am still a bit fuzzy on using pose and volume matching, so take the notes on those (including those in the bottom right) in the attached file with a grain of salt.
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