pyro rendering artefact

[dayvbrown]

Hi all,

see attached image for easy explanation...

This has just started happening in my pyro renders for one shot. I feel like i've switched something on or done something really basic, any ideas what this artifact might be?

I AM scaling the pyro after the fact... but i've been doing this all along with no issues.

i've tried various volume sampling and filtering adjustments as well as step size adjustments but no luck

I can't upload a file to look at unfortunately.

Any thoughts would be greatly appreciated.

Thanks,

Dave.

[dayvbrown]

righto so this is happening on the edge of the render tiles...

that might give more of a clue??

[LaidlawFX]

Food for thought;

A grid like artifact like that could be either you render tiles or based on your voxel grid, those are two common grid like structures.

Check to make sure its one or the other, since, that can be the root of two different problems.

To check 100% if the artifact is based on the size of bucket size do a wedge of the bucket size between, 8, 16, 32, 64. You can also use the render time image plane to check the size of the buckets to see if it corresponds. If it is I would dump your mantra rop for a clean one do a test. Go into a clean scene with the file to do a test. Bring in an old working pyro fx into this file and see if it works.

If its the voxel grid I would look at the different volumes that compose the sim and see if you can see in the viewport the same breakage and chase it back through that manner. If you are working with a "clear" view port that renders like that add density into sop land and subtract it as it comes into the shader. Test with a standard shader, if you do have a custom shader on it, you might have a wierd mult in the shader. It could be possible your doing a sop based scale that is stretching the voxels apart, maybe want to add more voxels or do it in comp.

[ikarus]

my guess is you have some crazy fast velocity field which causing weird sampling issues, perhaps increasing geo blur samples?

[dayvbrown]

Thanks guys much appreciated.

So i'm still not 100% sure what was causing this (however i do indeed have a crazy velocity field) but as it turns out in a fit of Deadline Induced Sleep Deprivation switching to the raytrace engine completely removed the problem. When i checked this morning my earlier files are indeed raytraced... incredible what a couple of hours sleep can do!!

Thanks again,

Dave