View Full Version : Nodes question

02-16-2007, 05:25 PM
Are things like the Color Tool full-precision? I've been looking for a way to take reflection shading say from the ani-reflections node and increase the contrast to simulate a reflective surface with non-linear response, like car paint, which might have high-reflectivity but only reflect the brightest elements of its surroundigs and absorb more sutble details. But the color tool makes me nervous with settings like "brightness" and "contrast 100%". Is the output still full-range in LW's internal sense, or does it output some 8 bits per channel crap? Is there a better way to achieve this effect? It seems to me a function-node would be more elegant for this, but I don't get why so few nodes have an input for one. I can achieve pretty much anything I can think of with the node editor, but I feel like there are often better ways of doing things than what I come up with, yes I've RTFM but I haven't gotten a feeling for it's "proper" use in terms of how it's various elements were designed to be used. Getting off topic, but if anyone can help, thanks in advance!

02-16-2007, 05:35 PM
From what one can see from the outside of nodes... all connections are floating point (except for integer connections, obviously).
Dont be mislead by the percentages, you can easily enter 5000%, or -2000% (internally 100% = 1.0 anyhow).

So the nodes should be full precision inside as well... you really have to make an effort to loose it (coding wise) ;)

Brightness and contrast are a bit different, but if the math is done right settings beyond the 0%-100% should work as "expected".


02-16-2007, 05:51 PM
Thanks mike

02-16-2007, 06:22 PM
Thanks Mike

02-16-2007, 09:01 PM
Actually, it appears my suspicions are true. I did a test where I took pure reflections (of an HDRI map) and reduced their level simply with the reflection percentage in the layers editor. Then I put a Color Tool node in the reflection shader path instead, and used the brightness/contrast to effect the reflection shading. The effect is more what I want to achieve (notice the deeper blacks), but as you can see, in the second pic, it clips the HDRI info, leaving the blown-out, grey highlights, whereas in the first the highlights are preserved. So I'm assuming the Color Tool is converting its input to 24 bit space before operating. What node can I use to achieve what I was thinking in my post?? Using say the gamma function on something like a spec shader does exactly what I'm talking about, but of course the reflection node has no fuction input, so I'm at a loss. Can I use a vector math node or something? Thanks

02-16-2007, 09:44 PM
Just fyi, it's a total kluge but using a math>vector scale for contrast into a math >vector add with neg values (for "brightness") does basically the same thing as the color tool but leaves the HDRI reflection beautifully intact, as you can see! Still wondering if htere's a better way to control the reflection shading contrast besides this, but there you go, the Color Tool's apparently 24bit only and definitely shouldn't be used in shader paths generated by lightwave (reflections, etc). Sorry if this is "duh" for ya'll, but it would have made sense to me to use it this way since the manual says nothing about this fact!