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View Full Version : Possible Tip for faster Dynamic Bullet Calculations



jboudreau
02-16-2014, 06:09 PM
Hi Guys

I'm not sure if everyone knows this or not but I was playing around with bullet dynamics getting a sign to swing on chains. I noticed when I set the chains to sub patch mode and did a bullet simulation it took a long time to complete the calculation. I was playing around trying to speed up the calculation and came across this tip. I set the sub patched object to first instead of last. This caused the bullet simulation to calculate very fast but at first the sub patch object was not working as stated in the lightwave manual (Make sure you set the Subdivision Order to After Displacement or Last for any Deforming Body sub patch objects or they will not work. Subdivision Order does not matter for polygonal objects.) so I thought the calculation didn't work at all.

After the simulation I set the sub patch object back to last and to my amazement the simulation had worked on the sub patched object. So if you set your sub patch objects to first before the simulation you will speed up your bullet dynamics calculation. setting sub patch displacement on my objects to last before bullet calculation it took 20sec to go 10% when I set the sub patch displacement object to first before the bullet calculation it took 2 sec to go 10% that is a serious increase in speed.

If you ever tried to do a simulation and then toggle sub patch on your object after the calculation the bullet dynamics always recalculates the scene. Changing from first to last after the calculation keeps the toggle sub patch object without having to recalculate the scene again.

Another tip when your object is sub patched you won't be able to see the simulation if you want to see the simulation just go into the bullet dynamics properties under the world tab and turn on draw collision shapes.

Hope this helps some people out there

Thanks,
Jason

erikals
09-12-2017, 01:55 PM
(Make sure you set the Subdivision Order to After Displacement or Last for any Deforming Body sub patch objects or they will not work. Subdivision Order does not matter for polygonal objects.)
hah, lovely, thanks!   :)
        (3 years later...)   :king: