Author Topic: Flickering with animated water  (Read 1373 times)

2018-06-26, 12:56:39

nauticus25

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I'm trying to render a water tank filling with water and am having some problems with flickering.  For the water object, I've used a box with an animated boolean to show the tank filling up.  On top of the boolean in the modifier stack, the box has a subdivide and then a Houdini Ocean modifier to give the top surface some waves.  The animation works great, except for flickering in many places.  It almost looks like the front face of the water gets all garbled up and the refraction gets all messed up.  However, I'm not sure it's a geometry issue because if I switch the viewport from camera to perspective and move the camera just a tiny little bit, the frame renders fine.  I would think that if it was bad geometry at that frame, the refraction would be garbled even if the camera angle was slightly different.

The water material is modified from the water that comes with the Corona Material Library.  I made it green and gave it some volumetric scattering to make it look more like rainwater instead of a pristine pool.

It was rendered with Max 2019 with Corona 2 RC4.

Any ideas?
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Max 2024, Corona 10

2018-06-26, 14:43:14
Reply #1

romullus

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Sounds like an issue with intersecting geometry. You can quickly check if that's the case, by isolating water mesh and trying to render it alone. If issue doesn't happen anymore, then it is likely that some faces of water mesh are coplanar with faces of another mesh (glass?).
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2018-06-26, 15:15:48
Reply #2

nauticus25

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I had to extend the length of the animation and modified some parameters in the Houdini Ocean modifier, and now it isn't glitching at the same frame that it was earlier.  I'm running another animation now and will report back if it still glitches.  I also just deployed the Corona 2 final release to the farm, so we'll see if that changed anything, though I was running RC4 yesterday so I can't imagine that would make a difference.
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2018-06-27, 14:26:54
Reply #3

nauticus25

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Well, the final animation rendered out mostly fine.  There was one frame where there was a little flicker, but over 40 seconds or so of perfect water.  I don't know if it was deploying v2 final or some minor change to the geometry.  I'm glad it went away, but I'd almost rather find out what the problem was so I can avoid it in the future.  Oh well.
i9-12900K @ 3.2GHz, 64GB RAM, 3090ti
Max 2024, Corona 10