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Physical simulation
About Truespace Archives
These pages are a copy of the official truespace forums prior to their removal somewhere around 2011.
They are retained here for archive purposes only.
Physical simulation // New Users
Post by 8-bit // Feb 2, 2007, 6:41am
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8-bit
Total Posts: 84
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When using the the physical simulation I find that objects can pass through one another or finish up laying inside other objects once they come to rest. How can I stop this? |
Post by hultek43 // Feb 2, 2007, 7:47am
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hultek43
Total Posts: 234
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See image below. |
Post by 8-bit // Feb 2, 2007, 8:45am
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8-bit
Total Posts: 84
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Ah thanks. ;) |
Post by 8-bit // Feb 6, 2007, 7:06am
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8-bit
Total Posts: 84
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It all works great now although I've noted some other strange behaviour. At end of the animation some of the objects seem to suddenly start moving around for no reason in strange patterns, backwards and forwards at times. Whats causing this? |
Post by Norm // Feb 6, 2007, 7:44am
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Norm
Total Posts: 862
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It is the "math" working. If the simulation is still running, the math is being computed. You can adjust settings to "calm" this if you want the sim to run longer than the "action" in the sim. |
Post by TomG // Feb 6, 2007, 8:11am
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TomG
Total Posts: 3397
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You may have left over keyframes from another phys sim too. It can go like this:
1. Run phys sim to frame 600.
2. Decide you don't like it and want to change it, this you stop at frame 560.
3. You decide to change it again, and make it all shorter, so you run phy sim to frame 500.
Your timeline now has your latest keyframes from 0 to 500, the keyframes from your second phys sim from 501 to 560, and the keyframes from your original from 561 to 600.
Of course at the transition point, objects suddenly jump around as the keyframes don't smoothly join together (since they come from different animations).
Might not be what you're experiencing, but I have had that happen. Check the Keyframe Editor and see if you have stray keyframes in there. Delete any offending ones. Another helpful tip is to delete all animation before running a phys sim again.
HTH!
Tom |
Post by 3dpdk // Feb 6, 2007, 2:52pm
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3dpdk
Total Posts: 212
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I have seen both effects described by Norm and Tom. If your collision detection is turned up, or elasticity is pretty high the object will vibrate around on the surface it's supposed to be resting on. If Tom's scenario is true, the object will appear to jump around, not smoothly, as it reaches keyframes from previous simulations that extend beyond your last simulation..
If you can't make it stop and there's other objects that are animated in the scene while this object is supposed to remain motionless, here's a solution IF the original object is not expected to interact with the other animated objects:
4208
Make sure in the simulation properties box you have "erase script" turned off and run the simulation on the object until it comes to rest (as best as it can).
Now erase all physical properties to the object!!! 4216 Do not try to run a physical simulation again on the object, but instead use the keyframe animation just created by the simulation.
4209
Advance the animation frame counter to the point where the object seems at rest and open the scene editor. Select the object and delete all keyframe diamonds after the frame you just determined to be the last in that object's animation. You can do this with a left click/drag and group select all the diamonds you want and hit the delete key on your keyboard.
4211
Your object now has a physically based animation that will run both during simulations of other objects and when playing the animation while "animate scene" (as opposed to "animate object") is selected. It will come to rest and because you erased all further keyframes, it will stay put.
4210 |
Post by 8-bit // Feb 7, 2007, 12:12am
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8-bit
Total Posts: 84
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wow, thanks for all your help. Another lesson learnt! ;) |
Post by 8-bit // Feb 8, 2007, 6:40am
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8-bit
Total Posts: 84
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Another problem seems to have occurred and that is when the blocks Im working with come to rest some seem perched on other blocks at very unnatural angles. Some are even leaning over but are not falling as they would in real life. What setting should I change, gravity? |
Post by Bobbins // Feb 8, 2007, 7:14am
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Bobbins
Total Posts: 506
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The geometry is probably intersecting and causing the objects to stick from the sound of it. The first thing to do is to increase the amount of geometry on the objects - add more faces or quad divide - and see if that helps. Next is to try checking the 'Constant Time' box in the simulation properties panel and try different values in the box next to the parameter. The higher the number, the more accurate the simulation but the slower it will calculate. |
Post by 8-bit // Feb 8, 2007, 7:28am
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8-bit
Total Posts: 84
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Again, many thanks. :) |
Post by Burnart // Feb 8, 2007, 11:41am
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Burnart
Total Posts: 839
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Good info in this thread - nice one guys.:) |
Post by 8-bit // Feb 9, 2007, 1:11am
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8-bit
Total Posts: 84
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Well its certainly helped me acheive what I wanted. :) |
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