I think I found at least one cause behind dForce explosions...

paulshaunblake

I doubt it's the only cause, but in my experience, dForce will go nuts when it has to deal with 30 or more polygons at a single intersection.

As a test, I tried making various primitive spheres into dynamic surfaces. Up to 28 sides worked without issue (although the default stiffness made the structures too rigid to collapse very much), but at 30 sides, dForce went berserk. At values higher than 30 sides, it just went more and more crazy.

Starting with a 64-side sphere, I edited the sphere in Hexagon, deleting the triangle polygons at the poles. I then selected to opposite edges on one pole and bridged them together. Next, I bridged all the other edges to the new surface. Last, I deleted the first bridge surface, and bridged all the new surfaces across that gap:

I sent that back into Daz, turned it into a dynamic surface, and simulated it from there - this time, it worked exactly as one would expect. The sphere collapsed neatly, without any explosions.

So, at least one thing that can help: Find spots on your model where lots of polygons meet at a single point, and tesselate that into a less complex spot.

And, of course, go ever so slightly mad as you try to fix the UV coords that winds up breaking.

Cris Palomino

Avoid high valence vertices. High valence vertices are a cauldron of conflicting forces waiting to explode.
 

Padone

In math every operator has a domain. And it's the same with programs.

In my opinion dForce should check the mesh and warn the user when it is applied to an unsuitable mesh. At least for the most common cases. So the user would know how the mesh needs to be modified and why. Instead of wondering why it explodes.

Richard Haseltine

Having the mesh checked (to the extent that that is possible) by dForce each ttime would slow the process down for all items (the check would have to look at both the mesh and at weight-maps, since an item might have problem areas zero-weighted to make it usable). Items that are marked as dForce compatible shouldn't have issues, for the rest people have been posting lists of what works and what doesn't.

DrNewcenstein

Another thing that causes explosions is if the dynamic item is pinched between 2 body parts, such as the arm and torso.

 

However, dForce now includes a function that shows and selects colliding vertices so you know what to edit before you run the sim. After applying dForce, go back into the dForce menu and click Select dForce Starting Collision Vertices. When it finishes, switch to Vertex Selection Mode to see where the initial collisions are going to happen, and if there's a problem from the start.

 

IsaacNewton

Richard Haseltine said:

Having the mesh checked (to the extent that that is possible) by dForce each ttime would slow the process down for all items (the check would have to look at both the mesh and at weight-maps, since an item might have problem areas zero-weighted to make it usable). Items that are marked as dForce compatible shouldn't have issues, for the rest people have been posting lists of what works and what doesn't.

The increased calculation overhead for mesh check at the beginning of a simulation is a good point, however it could easily be solved by having a "Check Mesh" tool as part of the dForce suite. This could then be applied when a new mesh is to be used with dForce or when a mesh is causing specific problems. However this would make it easier for users to apply dForce to third party items and thereby potentially reduce sales of specifically dForce compatible items.

DrNewcenstein

Then there will have to be some stronger selling-point for those items beyond "dForce Ready".

aaráribel caađo

Cris Palomino said:

Avoid high valence vertices. High valence vertices are a cauldron of conflicting forces waiting to explode.

What is a high valence vertice?

Richard Haseltine

aaráribel caađo said:

Cris Palomino said:

Avoid high valence vertices. High valence vertices are a cauldron of conflicting forces waiting to explode.

What is a high valence vertice?

A vertex where many edges meet - valence is, in this context, how many edges are at a vertex (presumably analogous with valence bonds, where electrons are shared between atoms in chemical bonds - in chemistry a valency over 4 would be suspect, in modelling 3-5 is the safe rnage and 3-4 is preferable).