blitz collisions
Blitz3D Forums/Blitz3D Programming/blitz collisions
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| What are ALL the known problems with blitz collisions?, im dammed if i know why my 'vehicle' is falling through the mesh. Its doing it on a point with no seams. It seems to do the sliding collision fine for a time, and then goes ape, starts twitching and then falls through the mesh. |
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| Point with no seams? One thing that frequently is driving me mad is when a elipsoid to polygon handling will fall trough the ground when there are overlapping horizintal polygons that have a gap like this:
chrarcter >>>>
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even if the gap is only a nanometer, the character will fall trough, although when watched from above there ain't no holes. So I always have to make sure the polyes are welded or intersecting. |
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| And I thought it was just me. I had to include code using TerrainHeight for both my characters and my camera, so that if they fell thru I could detect it and raise either back up to terrain level. And on a normal Blitz terrain! It seemed that if the incline was steeper than 45 deg like so _/ then either might pass thru, then keep dropping. |
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| Same here - floating point issue perhaps - related to collision radius size vs level mesh size (i.e. small col radius/ big level). |
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| Never had the issue with meshes falling through a landscape before .. does this only happen if a mesh is sitting static on the landscape for a period of time or even with constantly moving meshes? I did have alot of hastles with blitz versions < 1.88. Even with sliding collisions my meshes would sometimes stick to the landscape as if stop collisions were being used. God knows how many hacks I put in there to prevent it. When I upgraded to 1.96 this issue went though :) Stevie |
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| No, always moving meshes. But as you say, this may have been resolved by later than 1.88 compiles. I'd have to rem out the code to test it. |
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| Is it possible that the graphics card could effect collision problems? I haven't had these problems either. Some people used to complain about Morrowind (the computer game) whereby they would fall through the landscape etc - never happened to me once. Which makes me think 'Why is that' - surely that is hardware related? |
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| Sounds like floating point inaccuracies, although I am only going by what I've heard on the forums before - never had this problem myself, but then the largest outdoor environment I've used is about 2000x2000 (blitz units) with a character 2 units tall. Does this happen when the object is far from the origin (0,0,0), and how large is your environment? |
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| Damnit Matty, you beat me to it. I was helping PsychicParrot out with an issue like this a year and a bit back, you had to stop the player from going too far from (0,0,0) and when it did, move *everything* backwards by the same amount so you couldn't tell anything moved. This solved the random fall-through-floor problems :) |
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| Yes it was quite far from the origin, mabe 10-20K I have based it on the 'balls' to vector system Mr sibly put out in his 'driver' demo. at first i thought it could'be a ball getting stuck and sucking it through the mesh, but this appears not to be the case as it does the same when swithched off, and simply using the body to polygon. Morrowind (the computer game) whereby they would fall through the landscape etc This even happened on the Xbox version (bad coding i suspect ) Great game though ;) |
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| The system I used for quite a while was also based on the driver demo, and had the same issues :) |
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| I occasionally have it happen at something like 4096+ distance from 0,0. Levels with great height ranges and/or very large polys can also exacerbate the problem. And unfortunately it's a gamebreaking kind of a bug if it's not solved 100% all-of-the-time. |
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