View Full Version : dYNAMICS?: Ice cube

03 March 2003, 07:29 AM
I'm doin a couple scenes where ice cubes drop and in one case hits the floor and i would like it to break at least somewhat on impact maybe a corner on edge of something so its believable.....the shot is gonna be composited onto video and the shot is close up so its gotta look good.......Can anyone offer advice on the apprach....should i use dynamics or some other method and how do i make the ice cube solid so it can break or pieces can break off? I am clueless. Thank you in advance.

03 March 2003, 05:13 AM
Hi Andrei2k,

I think that there are fundamentally three ways to go about it. The first is to keyframe it all. The second is to let the dynamics do it all. The third is let the dynamics do it, bake it, and then modify it to your taste.

Essentially what I would do is build the cube cut up, keep it together and then break it on impact (either via keyframing it or dynamics). I sort of did a little test awhile back with a block breaking on impact in Lightwave that illustrate this process (just go to my site and at the bottom there is a link to free stuff... go there and check out the animation - it isn't the best effect (I didn't spend much time on it), but it should give you an idea of the effect). In that example I keyframed the big chunks, and let the dynamics do the dust and particles (which could use some tweaking).

Anyway, hope it helps.

03 March 2003, 10:20 AM
to add believabilty you'll have to add internal cracks as well. you can create an image of what you want the cracks to look like and then create a file texture with this image and map this to the refractive index (raytracing). then increase the alpha gain of the image file to 1.25 to create the refaction. if you use a projection to map the image to the ice cube then increase the projections alpha gain not the files.

you can key frame the refractive index to become 1.25 at impact.

good luck.

04 April 2003, 04:10 AM
Thank you for the replies if all goes well the input and my messing around with it should work...

04 April 2003, 07:40 AM
you may also want to think about using 2 cubes one for the fall and right when it hits you key it visablity of and turn on cube 2 (this is the broken one) cube 2 could have a bunch or chunks in it

if you use the ridged solver having the chunks right next to each other will most likely give you interpenitration errors so you could take each chunk at put it on its own collision layer and set the ground plane collision layer too -1 ...-1 is a global layer which effect all other col. layers

now you chunks may fly through each other but if the action is fast you may not notice

not sure if you can key the collision layer but if you can after the break up you could key them all back to one layer so they don't fly through each other

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