View Full Version : Maya 2011 fluid inherit velocity bug?
01 January 2011, 10:49 PM
I'm having problems with surface emitters emitting speed. Both add and replace cause the fluid to blow up. I'm using texture on the density and heat. Any ideas?
01 January 2011, 11:02 PM
Inherit velocity doesn't work well if the topology of the emitter mesh changes over time (i.e. the triangle count changes). Perhaps that is part of your problem. Normally an inherit value of 1.0 would be OK, especially when using replace. The add method might be too strong if the rate were high (like 1000). Or perhaps the mesh is moving very fast? Perhaps lower the maxDistance on the emitter( it could be adding the velocity to your entire fluid if the distance is too high).
01 January 2011, 11:56 PM
the velocity vectors seem to point to the origin cause when I moved the container and fluid, directionality changed to face the origin. tried those settings you suggested... no max distance, normal speed is 0, my rate is around 80, and its just a sphere with no deformation.
01 January 2011, 07:02 PM
I forgot... there was a bug where transforming the fluid container messed up the inherit velocity compution. (basically the transform is added to the velocity)
Perhaps you could work around this by keeping the fluid as an identity transform and using auto resize?
If you can't use auto resize another option might be to use the auto resize "dynamicOffset" attribute but with auto resize turned off. You can do this by enabling autoresize then setting the dynamic offset by hand and keyframing it to that value at the start frame(otherwise rewind will zero it). You can then turn off auto resize and the dynamic offset attribute will still shift the fluid position( without causing the inherit velocity bug ). I've not fully tested this trick, so it might have caching or rendering issues.
01 January 2011, 07:22 PM
What do u mean by an identity transform?
01 January 2011, 07:37 PM
The identity transform is the following:
translate = 0 0 0
rotate = 0 0 0
scale = 1 1 1
shear = 0 0 0
(basically no transformation)
01 January 2011, 08:20 PM
I tried moving the box to 0 but since the emitter isn't at 0, it still acts wierd
01 January 2011, 11:36 PM
As long as the translate is 0 0 0 and the scale is 1 1 1, you shouldn't hit the bug. (note that you can't group and then offset the the group... the start position of the fluid needs to be at the default location) The emitter can be anywhere. With auto resize it will automatically jump to the emitter location if need be.
01 January 2011, 07:58 PM
Thanks Duncan that worked
01 January 2011, 07:58 PM
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