Note: I've found and fixed the Color_Round bug. It's actually caused by a Math:Color_Sub (subtract) node being decoded incorrectly.

But I can tell you that even with my correction, subtraction doesn't work. There is no subtract "texture" in Lux. I thought I had a solution using "mix" but it turns out that Lux refuses to mix negative colors. It just does not tolerate the idea of values outside the range of 0 to 1, even if they are brought back into range later. So it is pretty much impossible to do math, other than multiply, in Lux shaders. And even then, the values are often clamped to the unit range.

The designers of Lux don't really grasp how procedural shaders are done. The only way I'm going to be able to implement the kinds of procedurals we use in Poser is to change the C++ code, which I plan to do.

It has some nice pattern generating functions, but you can't combine them in all the ways that are needed.

For example, yesterday I tried to use the Dystopia city set. In there is a procedural for slightly rusty galvanized metal. The look of galvanization was accomplished by taking a clouds node, multiplying it by a large number, rounding that off to an integer, then dividing by the original large number. The result is that you get chunks of solid gray in various shades, instead of a cloudy pattern. This is a very common technique, and impossible to do in Lux procedurally.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)