avoiding moire patterns

[siliconbauhaus]

I'm trying to render out some image to get a job out and I have a gradient map bump to make corrugated sheet.

The first two renders were fine but this next view I'm getting moire patterns on it and it's an arse. I'm trying to avoid cranking up my aa as these are slow enough already.

Has anyone else had this problem and come up with a solution?

[RErender]

What AA filter are you using?

The filter can have a big impact on moire .

Some good examples in the manual http://www.spot3d.com/vray/help/150S...ge_sampler.htm

[^Lele^]

Use bitmap filtering where possible, and a blurring AA reconstruction filter (area, for example) with a bigger pixel size than usual.
Rendering a pass of the object wherever possible should help avoid changing the look for the entire image.

[siliconbauhaus]

I wasnt using any filter for the AA but I had changed the blur from 1 to 0.1 so maybe that's contributing.

[MikeHampton]

Unfortunatly any time you have detail below 1 pixel you might run into moire patterns. The AA settings and the resolution you are rending out have everything to do with this.

If you have tried everything you can with AA... you might try using a standard max material (if it's not already a standard material) and turn on supersampling in that material and try different types of supersampling.

[siliconbauhaus]

The annoying thing is it seems to be related to camera angle. I'll get some area where it happens and others where it doesn't.

[RErender]

More the angle of incidence than the camera angle per se, as you get more parallel to the surface, the details get closer together causing the moire.

[MikeHampton]

Another thing you might try is to increase (exagerate) the uvw mapping of that object, in effect increasing the size of the maps on the object. Or if the fine detail is in the geometry, increasing the size of the fine detail so it's not quite so small. In your example it would be increasing the size/spacing of the corregated metal (weither it's a map or geometry).

You just may be able to make a small increase in size just enough to get rid of the morie patterns but not enough to make the size of the object/material look "too big" or out of scale.

Or you might try blurring the image. It's amazing how blurry photos/film are compared to the typical razor sharp design rendering. But that blurriness is what helps to reduce/eliminate morie patterns.