Jump to content

Spline/Tube collision detection methods


rickyjohnson
 Share

Recommended Posts

I was hoping that somebody could give me some advice on how to achieve a good collision detection/physics model in this scenario:

 

I'm trying to model tassels on the end of a throw. They're supposed to be a pretty chunky knit so my intention was to get a spline prepared for each one and then use them as a path for a Path Deform on the knit geometry (whatever that ends up being). The only thing is I can't arrive at a decent simulation for a bunch of splines (with a given thickness for the purpose of the simulation) that need to respect collisions with their neighbouring splines and also with the geometry that they're being draped over.

 

So far I've tried the hair & fur modifier in Max: the physical simulation of the Guides just goes haywire when they meet a collision surface in anything other than the most basic of scenarios.

I've also tried setting up 'ropes' in Mass FX using about 15 bone segments with constraints as joints: Again, in a really basic scenario (1 rope being draped onto a plane) this works fine. If more than one of the 'ropes' is placed side by side anywhere near one another the simulation just goes haywire again with ropes flying all over the place like a hydra! Also, it barely seems to cope with any collision meshes much more complex than a box (I'm aware of the 'hull mesh' creation process within Mass FX so think I'm doing this appropriately).

 

With the settings on the Max simulations - I'm no expert but I've spent a day on this looking at various tutorials and the available help and I can't see any way to push the settings that would help to solve these collisions any higher than I have tried.

 

I've also tried using inflated tubes in Marvelous Designer: The collisions are much better but the set up is very awkward and extracting splines from the resulting triangular mesh central to the volume is going to be pretty painful.

 

Surely this type of simulation is possible? Especially when you see the level of simulations that people working in VFX create for instance. Is there particular software that might be better for this?

Not that I can justify much expense for the sake of tassels but it would be nice to know if the 3ds Max systems are a bit useless rather than the way I'm using them!

I'm curious as to why the collisions in Max seem to buck so violently when an intersection is detected. Wouldn't you try and develop the simulation so it slowed right down in this situation and would try and gently move the offending elements apart rather than rapidly flinging them in opposing directions? I've noticed this violent movement at times in Marvelous Designer also although it generally behaves a lot better than the options I've experimented with in 3ds Max.

 

Anyway, and ideas or insight would be much appreciated. Thanks!

Link to comment
Share on other sites

in massfx have you tried increasing the damping and the substeps? The simulation time will be longer, but generally more accurate.

 

 

 

I did try that with the substeps, yes. I set the figure for substeps as high as Max would allow me in the end (159) along with the highest allowable solver iterations. Still it's no good. I don't mind how long the simulation takes (within reason).

 

 

I didn't experiment with any particularly high damping. I will give that a go.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...