Yea, so I stupidly took a beta from SM and it crashes immediately. I have to re-install. But meanwhile, people are coming over.

I'll just point out some tips for now.

Once you learn a few basic ways of replacing colors with other colors and a couple patterns, this stuff is pretty easy. The grief is that testing with 10,000 leaves is slow. If you can find a prop with just a few hundred, I'd give that a go.

First tip - take your leaf color map and run it into an HSV node. Set saturation to 0. Adjust the HSV "Value" parameter to get the brightest result to white or close to white - this may need to be above 1. This is now a useful black-and-white pattern which can then be easily colorized. (There are more tricks we can play with HSV but we'll "leave" that to later. Get it? "Leave" it - aaaa hahahahahahah)

Try this now - take your HSV B&W output into wherever the color map used to go (probably Diffuse_Color but if you know shaders, you're probably using Scatter here.)

Set the color chip where you plugged it in to any color you want. Now you can get a red or yellow leaf from a green color map.

OK so keeping that idea in mind we need a pattern.

These modulated patterns are easily produced using Poser's 3D noise nodes. The two most easily used in this case are probably Spots and Clouds.

Try a spots node. It has two color chips - use your B&W HSV for both. Set one to yellow, the other to red. You'll probably want to increase the scale on the spots so they make big areas of color on your leaves. Increase the softness to get smoother transition between your colors and adjust the threshold to alter the ratio of the two colors.

After you get the hang of that, try the same with the Clouds node. Try big scale, little scale. Use the bias value to favor one color versus the other. Use the gain value to alter the contrast between one color and the other.

Removing leaves is similar - you use a spots node (black and white) with no softness so you get a sharp edge between visible and invisible leaves. Plug that into transparency and set that to 1. Set transparency_edge to 0. If you have specular turned on somewhere, plug the spots into that as well to modulate the reflectivity of the specular. You need specularity to be 0 (black) exactly where you also are invisibile (black).

Of course there is still the question of how to make a good leaf shader, but that's separate from the mechanism of modulating color and transparency.

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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)