shader mixer: reflective surfaces

sriesch

I'm looking at the example chrome.duf shader that comes with studio to learn how to use reflective surfaces, got an experimental material working ok, but have several questions.

1. What controls how reflective the surface is (dull, highly polished, etc.)? I see the Value(5) brick controls the color, and of course you can make the color brighter and darker, but (unless I'm looking at it wrong) that's not the control I'm looking for.

2. What is the purpose of the "Caustics [Surface] (4)" brick, and why doesn't my Surface brick have the "Root Settings" parameter it plugs into? I don't know if I need to add this brick to my shader network or not, but I'm assuming it's there for a reason even though I can't see the effect in my tests yet, but don't know how to add it.

sriesch

Just found the missing "Root settings" parameter, I just needed to click on the brick's menu and select "show advanced".

mjc1016

First, you need to click on the little arrow in the upper right of the Surface brick and then 'Show Advanced'. Then the root settings will show up.

That's one of the functions of the caustics brick, as it is set to 'chrome' which is predefined to provide the 'proper' reflectance for chrome.

sriesch

I have added the caustics brick referred to in question 2 to my network, although I haven't found a way to see what effect it has yet.

I have a third question to add to the pile:
3. I'm hazy on exactly what the Trace brick is doing, beyond the brief description in the manual, so I'm not sure if I'm doing this the right way. I fed the output of a Marble brick (through a Clamp Or Step brick to let me tone down the effect a little) into the Trace brick to give the otherwise reflective surface tarnished spots (top small screenshot, and shader Mixer preview). However, I've just realized that if I delete the skydome in the scene, the effect disappears completely (bottom small screenshot). Obviously deletion of the skydome will have a big effect, however I expected the tarnished spots to still be visible, such as where the light or reflections of other objects in the scene are visible. Am I trying to apply this effect in the wrong place in my shader network? The answer to this might possibly be related to question 1.