Displacement artifacts

[timmatron]

Could somebody please tell me what is causing this terrible noise/pattern that happens when I use a displacement map to get this scalloped pattern? I am using 2d, and there is only one polygon that its being applied to. Changing the resolution affects the pattern, but it never goes away. I've tried everything I can think of, but without success.

[vlado]

What kind of file format are you using for this? It looks like insufficient displacement levels in the file. Perhaps you can try increasing slightly the blur value for the bitmap, it may help.

Best regards,
Vlado

[timmatron]

I tried .psd and tiff formats. I also tried 16bit grayscale, although it was only made in 8. Its about 1400px wide, but I also tried changing it to 1024.

I'll try blurring it and see what happens. Thanks!

[vlado]

I also tried 16bit grayscale, although it was only made in 8.

That won't work, unless you also downsample it in 16 bits to get some extra levels. Blurring should help in any case, I think.

Best regards,
Vlado

[timmatron]

Well, playing around with the size and blurring of the map definitely affects it, I just haven't found the right settings to make it totally smooth. It seemed to work a little better reducing the image size down to about 512.

But I think for my purposes I can get away with it how it is now. Thanks for the response!

[Morbid Angel]

curious as to how you generated that 16 bit map?

[timmatron]

curious as to how you generated that 16 bit map?

Not properly I'm sure. I just took the 8 bit image and converted it to 16 in photoshop, hoping it would make a smoother gradient. It didn't really look bad on screen, thats why I'm surprised it came out so bad in the rendering.

I didn't take the time to make a new 16 bit image from scratch, but maybe that would work...

[Morbid Angel]

you cant simply take an 8 bit and convert it to 16 bit. It will not contain the same range of data as a true 16 bit.
The best way for you is to start from scratch in 16 or 32 bit space. Or, use a program such as mudbox or zbrush to generate a true float image.
What you are seeing in your render is simple banding of gray values typical to 8 bit.

[timmatron]

Yeah, thats what I was starting to suspect! Good to know for next time. I'm a little surprised though that I couldn't adjust the settings in either the displacement or in the map to smooth it out.