You’ve likely heard artists harp on about how important “attention to detail” is.
Because believability is half our job. We’re trying to make an audience accept a computer generated image – which is harder than it would seems.
So to do that you need to give them every bit of help you can to sell it to them. That’s why noticing small details from the real world, and integrating them in your render is such a vital skill, and the reason most cg job descriptions explicitly state you need it.
A few weeks ago I showed you how to create easy grunge, and this time we’re making dust.
Dust is made up of tiny particles of various different materials (soil, skin, hair, plants, you name it) that float around in the air and then settle on surfaces. Since these particles are so tiny, static cling lets them stick to any point on a surface, despite gravity constantly trying to pull it off.
This means that you’ll always have a very fine layer of dust covering the whole surface of the object, as well as a slightly thicker coating sitting on the parts of the surface that face upwards (where gravity can’t pull it off).
Hope it helps you get that extra level of realism in your renders.
Make something cool with it? Post your results in the comments below!
Lets take a squeaky clean Buddha statue…
What we want to do is essentially create two materials in a single node tree – one for the original blue material, and one for the dust:
And then all we need to do is create a mask to put the dust in the right places.
So remember more dust forms on the top of surfaces where gravity can’t pull it off? To do that, we can just grab the geometry Normal:
The blue channel of the normal gives us the Z-axis – which shows us which parts of the geometry face upwards and by how much. It’s also important to add the Mix node on the right to clamp the values, since the black parts of the surface actually have negative brightness which will break the math in the next step.
Also remember that dirt is more visible when viewed from a low-angle. To account for this, we can just mix in some of the Facing output from a Layer Weight node:
And that’s our mask!
So just plug that into the Mix Shader which mixes the clean blue material and the dirt material, and we’ve got ourselves a layer of dirt!Close Summary