now to one of the silliest test renders ever

altfog1amp1 It’s something I call “RiFog Plus”; and I have no idea if it will be shareable when I’m done with it. For simple reasons: a) it’s built off the “RiFog” example from the shader builder volume folder; b) the altitude code is lifted as-is from the altitude fog shader I found in the RIB Mosaic package (the RIB Mosaic itself doesn’t seem to work with the latest Blender builds, pity); c) I want to add good AA’d noise to it, and the only way I can do it is by copying some publicly available noise code. The whole copyright law thing is something I don’t understand well, and when it comes to re-using bits of these sample shaders, I don’t understand it at all.

Anyway, what it is is an aerial perspective shader, very simple and almost free in terms of rendertime. Not a real volume. But it should be really really useful for outdoor renders… especially with the noise part in.

I guess I should also add parameters to control the distribution – I already have a multiplier in the distance exponent (simulates the “density” of the fog, i.e. falloff), and I guess a similar one should be there for the altitude part, to have the transitional region more compressed or spread wider. And simple switches to disable either of the distributions in case they aren’t required for a particular look.


8 thoughts on “now to one of the silliest test renders ever

  1. The R__Fog is actually the same as the ‘standard’ from almost any other Renderman source…including K3D and aqsis…and it’s the same as the Renderman stock shader from Renderman 11.

      1. Now, there’s the tricky part…

        I know that one imports easily, so shouldn’t ShaderBuilder create the dzs file for it that is essentially the same (until you start adding your bits to it)?

          1. If you can find it, I think a good starting point would be the noisy fog in Rudy Cortes’s RSL Guide (I think it’s the first edition). Or even just his fog, as it has altitude included…and he’s made the shaders in it public domain (says so in the header/copyright info in the sl files). The noisy fog does compile in Studio, but I think it needs to have some work done on the various coordinate transforms it does, because they are not 3DL ‘correct’.

            1. I think I do have noisy fog and I tried doing something with it a while ago, but you’re right, it’s not DS-compatible out of the box. But a neat suggestion, thanks!

  2. A nice addition to the toolbox…except for the ‘unknown’ qualities for the ‘intellectual property’ rights parts of it.

    If you wanted to argue the case, at the very basic level, it’s nothing more than a mathematical formula and shouldn’t be able to be copyrighted, but…

    The altitude code should be ‘safe’ as it is actually a K3D shader.

    The RI_fog…now that’s the tricky one. It’s actually a standard RI shader, defined in the RI_Spec…but…

    1. Yeah, on the one hand, I don’t think DAZ asked anyone when they made their shader builder examples… on the other – who knows. When it came to the example scripts, the DAZ support told me that the examples are supposed to end up on their wiki some day DAZ soon (c), so everything’s fine if the CC license the wiki uses is accounted for. But shader builder stuff?

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