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View Full Version : Collision calculation takes so long



dankayaker
05-05-2009, 07:41 AM
I'm curious why this takes so long. I have a ring model with about 50k polys and a reflective floor (box). 300 frames takes like 15-20 hours on a new Mac Pro dual 2.2 (8 core) w/ 6 gigs ram. The odd thing is that the activity monitor indicated the Mac is barely working . . .allocating like 6% of the CPU.

joelaff
05-05-2009, 02:44 PM
The dynamics engine is still single threaded. That would explain the usage.

You might try using a simplified stand-in object for collisions. Also, perhaps the precision is set to high for the scale of your object? Perhaps try tripling everything...

dankayaker
05-06-2009, 08:51 AM
The dynamics engine is still single threaded. That would explain the usage.

You might try using a simplified stand-in object for collisions. Also, perhaps the precision is set to high for the scale of your object? Perhaps try tripling everything...



Thanks . . . I'll try checking my percision (where is this ?). What do you mean by "tripling" everything . . . I'm not expert . .sorry.

joelaff
05-06-2009, 04:36 PM
By tripling I mean converting everything to triangles in Modeler. The command is called Triple.

I think the precision has moved to one of the tabs for the HardFX properties ("etc" maybe? I don't have it open right now).

dankayaker
05-12-2009, 12:33 PM
Well I've tried tripling and everything else I know and it looks like if you have a high poly count (1 object @ 500K) plan on spending 12-24 house with a spinning beach ball and then LW telling me the calculation failed.

How could something like calculating use such a small amount of processing power ??? This is just disappointing.

Surrealist.
05-12-2009, 12:59 PM
50-500 K is way to many polygons to try to be calculating dynamics on one small object. Remember that it is taking into account ALL of the points. For the calculation you only need the points that will collide. So the solution is to make a proxy object with the minimum collision points, and as pointed out, calculate that and use the FX hard link in the displacement pull down of the Deform tab. It won't distort the object, just mimic the motion. You have to parent to the object as well if I remember.