assign multiple materials on one DMM object

[newtonboyy]

I have a scene where i have the gound cracking and exploding, and I would like the cracks to be very tough, so I have that setting correct. However when I eventually explode through the ground, I would like more pieces to seperate. So I thought possibly assigning another material for just those pieces (this is all one DMM object). Is it possible to assign multiple materials to one object? If so, is there a guide to it? I tried a couple of things and nothing worked, such as trying to select faces and apply a new material. That didn't work.

Any help would be great. thanks!

[mandark1011]

first thought is create two pieces..laminates on top of one another...the top one being the super tough the bottom fracturing into multiple pieces..smaller, depending on how explosive your breakout is this should help to fill out the sim.

As far as adding multiple materials to one mesh I dont think this is possible in DMM at least not the Vanilla Maya version.

[newtonboyy]

That sounds like a pretty good idea. Thanks for the quick reply! Yeah I saw in the documentation about multimaterials but it was only a mention and couldn't find anything further. It would be great to be able to do that. Maybe in a future version. Thanks again!

[vik]

You might also try adding passive DMM objects around the crack to control how fracture happens. For example, if you don't want pieces flying super-high from random sudden impulses from driven objects, adding a DMM "dampening" slab can be useful.

You can also get great results by using splinters. Use a the autocage tool to create a very highly tesselated non-DMM object and then use that as a splinter cage. It works quite well.

-Vik

[newtonboyy]

Hey Vik,

Yes those splinters are wonderful! I'm actually using a voronoi fracture script to create the splinter cage for the rocks that fly up and it's working out quite nicely. The one issue that i'm having is when I turn the toughness up too much on my material, my smaller pieces don't seem to want to break apart, although in those areas I have a high density region and the splinter cage is very detailed. When I turn the toughness down, the smaller pieces break up but I get undesired results from the cracking (too much movement).

The "dampening" slab sounds very useful, but i'm sure I know what you're talking about. Is that a dmm specific object? I don't see a "dampening" object of sort in the menu's. Or is it something just using maya fields?

[vik]

By dampening, I mean a DMM object (just make a standard cube and stretch it out as you need it. Make the object passive and position it above where your fracture happens. If you position it close enough, you will keep pieces from flying out and the fracture will look more natural (if you are trying to do dirt for example).

-Vik

[mandark1011]

Use a the autocage tool to create a very highly tesselated non-DMM object and then use that as a splinter cage. It works quite well.

-Vik

Could you explain this a bit farther Vik? Specifically why youd use autocage and the high tesselation. Im not sure what benefit this has over creating a splinter cage using maya primitives then combining afterwards.
Thanks