Intermediate or edge/face particle creation?

[josemendez]

Thanks so much jose, I appreciate all of the information and the patience you've shown explaining these concepts to me.

No worries, that's what I'm here for

What I want is to be able to connect the top and bottom parts somehow without overconnecting everything else. That's why I suggested maybe a new way of connecting particles (other than cluster radius)

In that case, you'd have soft caps (bottom and top of the capsule) and a completely rigid mid-section that doesn't react to collisions (since there's no particles to collide). Colliders and other softbodies would pass right trough the mid part of the capsule.

maybe generating intermediary particles to get around that problem. I know that the end result wouldn't look good if we're deforming it as you showed in your helpful example. But wouldn't it still do a decent job of impact deformation like your barrel example?

Generating intermediary particles is ok, but that you can already do by using a subdivided mesh to generate the blueprint and skinning the original, unsubdivided mesh to it. However if you already have a subdivided mesh for particle generation, what's the point in using the original, unsubdivided mesh for skinning? (which will look worse). You usually do it the other way around: use a low-quality mesh to generate particles, then skin a high-quality mesh to it.

To come back to this point, maybe I'm misunderstanding the tool but doesn't Obi Softbody simulate collision and stuff too? The idea with adding those extra vertices isn't to improve the deformation (because obviously it won't, there are no more vertices to deform). It's to fill in the gaps so we have regularly spaced particles, both so we can connect the particles together easily so that other softbodies on the solver can collide/interact with it well. Is that the wrong way to do this? [...]wouldn't it still do a decent job of impact deformation like your barrel example?

Yes, having denser particle sampling in regions with no/few vertices would allow for collision detection. However collisions *always* cause deformation since they push particles around (impact deformation, as you describe it), so objects would clip trough and look wrong: colliders & other softbodies would sink into the mesh when colliding, as the particles deform but the mesh doesn't. Sketched it for you (the sphere pushing from above would be a collider, and I've only drawn the relevant particles):

   

Only case where deformation would not happen as result of collision would be a completely rigid softbody. But if you have a completely rigid softbody, you might as well be using a rigidbody which is a lot cheaper to simulate and will look much better.

Softbody = deformable body = you need vertices for good deformation. What makes sense in pretty much all cases (and what all physics engines do) is to have a high-quality mesh for visuals and a low-quality, simplified physics representation of it, not the other way around. Thats' why blueprints start with one particle per vertex -max quality-, and can only go down from there -proggressively lower quality-.

If you *really* wanted this for some reason (w/ collision clipping and derpy deformation), it would be possible to do it by:
1.- voxelizing only the surface of the mesh, projecting the resulting particles to the actual mesh surface. This gives good particle coverage regardless of mesh topology.
2.- generate clusters by distance as usual.
3.- profit!

This is basically a blend of volume and surface blueprints, I can get it running for you and have it ready around next monday/tuesday. Let me know if you're interested in it.