Odd artifacts in base images

Steel Rat

I've replaced textures on surfaces quite a bit, most of the time without issue. But sometimes weird things happen for no reason.

For example, adding an image to a TV screen surface, pretty trivial. But when there is text in the image, sometimes weird things happen.

Image 1 is the rendered result of image 2 when applied to the base color Iray surface.

 

DireWorks

looks like you didnt changed the emission color texture :) use the same as the base color

Gordig

How does it look in the actual render?

PerttiA

Compression algorithms do have problems with some colors/combinations, was the image a jpg file?

Iray does compression also when sending stuff to GPU and this can also cause compression related problems.

Steel Rat

DireWorks said:

looks like you didnt changed the emission color texture :) use the same as the base color

Same image for base and emission.

Steel Rat

Gordig said:

How does it look in the actual render?

Top image is an actual render, not a saved draw.

Steel Rat

PerttiA said:

Compression algorithms do have problems with some colors/combinations, was the image a jpg file?

Iray does compression also when sending stuff to GPU and this can also cause compression related problems.

Yes JPG. I just tried PNG and then TIFF. The results were less dramatic, but still not right.

Spacious

If you need that particular image to render without artifacxts you've got two choices.

1.  Go into the advanced settings tab in the render settings pane and set the texture compression to higher numbers so that iray does not compress textures as much.  The drawback to this is that it will not compress any textures as much and therefore will take more vRAM and longer to render.

2.  Reduce the dimensions of the image you're using so that it's below the iray texture compression levels that you're otherwise happy with.  The drawback here is that if you reduce the image size to smaller than it apears in your render then it will be pixilated.

Usually a combo of both is best.

Steel Rat

1.  Go into the advanced settings tab in the render settings pane and set the texture compression to higher numbers so that iray does not compress textures as much.  The drawback to this is that it will not compress any textures as much and therefore will take more vRAM and longer to render.

That's what I ended up doing. I'll have to experiment further, but at least I'm able to render without the compression artifacts.

Thanks PerttiA and Spacious!