101 question bump map question for a Brain Dead moment.

[Kinetic99]

Hello and thanks for your time,

I'm having challenges mapping on a fine noise bump map onto a surface!

I have a large multi-quad plane surface with a small relief-like design that pops out of it on the depth or Z-axis. If the plane is 10 x 10 units large, then the depth height of this relief is about 0.1 units high! Very soft relief but clear and obvious.

I want to create a sand blasted-like texture onto it and part of the material solution is to use a noise map with a fine grain size in a Vray mat. Eventually I will use it for rendering still images and animations of the object moving about.

The problem: I cant get it too look good! It does not map smoothly across the surface. If I use Explicit mapping with Box, my UVW are 10:10:10 (even though my plane is 10:10:0.1). This applies the noise all across the relief but in a muddy way. If I lower my W value, then I will be missing noise pattern on the relief. If I use Object mapping with Box, with UVW at 10:10:10 it looks a little better but I if I animate the plane moving or camera view, then noise pattern moves around in object space and you get that strange moving shimmery effect to the noise. If I use planar mapping (so 10 x 10 x 0), then there are missing areas of noise pattern where the Z-heights are more angular and higher and the noise starts to swirl around and look bad.

I just want to map a fine noise pattern that looks good a very low relief model in a very smooth and consistent way ( as if the noise pattern was nicely draped over the relief geometry) and have it look good in the lighting and stay put!

What am I doing wrong? Are there better solutions?

[joconnell]

Pop up some test renders of what you mean but I suspect this is an anti aliasing problem really. The issue is that a very fine bump map to the anti aliaser looks very similar to noise, which ultimately it's trying to smooth out. What might even be worth a look is rather than using a noise map which has infinite resolution, use a really high res texture of noise which will eventually run out of detail and allow the renderer to resolve it.

[Kinetic99]

That could contribute to the problem. My test renders at low res and just 1/4 Area looks rather smooth and acceptable. But when I up it to 1/6 Area with DMS on, I notice the artefacts of the noise pattern even more. but I do like your idea of placing a high res TIFF of a noise texture in the bump channel instead of a procedural.

Pop up some test renders of what you mean but I suspect this is an anti aliasing problem really. The issue is that a very fine bump map to the anti aliaser looks very similar to noise, which ultimately it's trying to smooth out. What might even be worth a look is rather than using a noise map which has infinite resolution, use a really high res texture of noise which will eventually run out of detail and allow the renderer to resolve it.

[joconnell]

Might be a totally crazy idea but would it be worth actually exploring rendering the tiny bumps? If you have something like forest pro it might be worth a look? There's a discussion about sparkly materials happening at the minute and some people are trying to use things like tiny particles to represent the little bumps and imperfections in a surface - they're getting really good results and it might be actually easier for vray to resolve too!

[rjohnson33]

Might be a totally crazy idea but would it be worth actually exploring rendering the tiny bumps? If you have something like forest pro it might be worth a look? There's a discussion about sparkly materials happening at the minute and some people are trying to use things like tiny particles to represent the little bumps and imperfections in a surface - they're getting really good results and it might be actually easier for vray to resolve too!

Is that technique being discussed in a thread on the forum here or maybe on the Forest Pro forum? I couldn't see anything obvious. Sounds interesting.