Scaling objects in iray and atifacts

Bobvan

At times when I enlarge objects I get some mesh lines showing and slight distortion on textures (rock in scene) I have included my texture compression settings. At times I can resolve this by tiling but not all textures can be tiled. Should I be making the texture settings bigger Is this a limtation of iray ? Any advice would be appreciated. I dont get this with lux..

acanthis

At last ... somebody else is seeing this problem!

I've been coming across this issue ever since I started using iRay. What you see is a fine checkerboard, or moire, pattern "bleeding through" the texture. I see it a lot on lower resolution textures in closeup, especially when the camera angle is near perpendicular to the surface and the light source is strong. I think it must be something to do with the algorithm that iRay uses to resize textures, but it surprises me because I would have expected that the texture would simply become indistinct or blurry if resized too much. The weird thing is that the checkerboard pattern is always the same scale in the rendered image.

The only solution that I have ever found for this problem is to resize the texture. In one scene I had to resize a ground texture to 8000x8000 to get rid of the effect.

Bobvan

Thanks. As you know I do land of the giants based stories so 95% of what I do is scaling. The other strange thing is I can make characters down to 10% and get no distortion unlike lux that gives them artifacts, the solution in lux is to make the sets huge sometimes as high as 800% plus without any problems or distortion. Thanks for the texture size suggestion will give it a try. The work around was to lux render for the one panel.

acanthis

Bobvan said:

Thanks. As you know I do land of the giants based stories so 95% of what I do is scaling. The other strange thing is I can make characters down to 10% and get no distortion unlike lux that gives them artifacts, the solution in lux is to make the sets huge sometimes as high as 800% plus without any problems or distortion. Thanks for the texture size suggestion will give it a try. The work around was to lux render for the one panel.

The other solution, which you have already discovered, is to use a tiled texture. I have also seen this problem with legacy hair and clothing, when rendering closeups. Interesting what you said above: I must admit it had never occurred to me that scaling the objects down might be a possible solution to the problem; I will have to look into that.

For your LOTG renders wouldn't it be better anyway to have the environment at 100% and scale down the figures? Although I suppose either way you are going to have texture quality issues because a lot of ground textures are not good for really close shots.

Bobvan

Ground, furniture ect many things do. Funny how its not an issue using lux, but lux still has glacier long render times for the most part so uisng it for the odd panel is ok. I have enough experience that I can more or less make the lighting match in both engines..