Author Topic: Height based dust  (Read 1545 times)

What is the best way to add dust so it accumulates in crevices such as screw indents? I suppose you need a height map and then add some effect, but baking a height map is not supported...

How about a CURVATURE map?

Watch this, see if it's what you're looking for...

Most of this video focuses on "outer edges" but you could invert it and work on crevices.
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Thanks, that did indeed work to some extent. There is a bit of an issue though. It is hard to fill the entire gap. The sliders Sharp, Fine, Soft, and Medium are at 1. This is with the mode set to Cavities. If I move any of the other sliders (large, big, etc), the dust will end on top instead of in the dents.

I suppose a height map won't work either because if the gaps are bigger, it actually should look like the screenshot.

A physics based approach would work better I think. In reality the dust accumulates in places where airflow and "touch" is limited. To simulate this with a curvature map is hard to get it look right.

Using the AO channel in the Mask Editor might also help, but I can't make it look realistic with that either, because the AO map itself looks similar as the screenshot below...

The Top Down gradient variable in the Mask Builder looks promising (that way you can modulate between curvature and "height"), but it seems you can't change the axis.
Last Edit: June 13, 2016, 04:03:02 pm

I'd say that AO map is the closest map to describe the area where you would like to get this effect. However, as you can see, it can't be used "as is", so you have to modify and/or combine it in some way with other maps to suit your needs.

I would suggest to approach this task like this:

First, use any generator or other means necessary to create the dust/dirt effect you're looking for without even bothering of how well and where it allocates. It may well cover the entire model, but that's okay for now. Look only for the visual qualities you desire.

Second, use inverted AO map as a mask on the layer/layer group created in first step. Set this mask layer blending mode to Multiply - with inverted AO, it will mask areas that are in the opening and reveal only areas with crevices (occluded). You can try some other "darkening" blending modes if Multiply feels not good enough, or use some Levels to modify the AO map to make it more contrast (for sharper transition in the mask). Try to use Blur effect to additionally "extend" the AO map to the areas where it's not strong enough (like in central areas of indents on screw shown above). As an alternative, you can try to bake the AO map with different settings just for this mask, trying to make it a bit more "broad".

In general, I highly recommend study layer blending modes available in Painter and try to experiment a lot with combinations of different baked maps, procedural textures, Mask Builder and general layer masks. It's a bit tricky to get a feel on it, but once you catch the idea — you would be able to get almost any effect you want on any surface area of your models. You'd be surprised how much can be squeezed from it  ::)

Let me know if this is too confusing and I will try to put together some pics for you.

Last Edit: June 14, 2016, 04:10:58 pm

Thanks, I will try that. If you have some pictures, that would definitely help.