Nodes Help

[gordonrobb]

I never really got into nodes with Lightwave. I've managed to get some fairly good and complicated textures using the old system, so didn't try. Now I find I'm not only having to learn nodes, but battle with understanding which nodes will and wont work with Octane nodes.

My challenge would be system in the old texturing system, but struggling.

I have a black and white image that is being used for Specularity, and I want to invert it and use it for Roughness too. I can either have a separate texture node, or use the invert node - got that bit sussed. However, what I want to do is be able to reduce the difference between the black and white bits, but be able to control the over all roughness separately.

To explain. Lets say in the image the contrast goes from black to white. that would (I imaging) be a roughness of 0 to 100% (I'm assuming black is 0). I'm guessing that if I reduce the strength in the image node that I am 'flattening' the difference, but loss the ability to control the base roughness. So for example, how would I have a base roughness of 50% and use the image to have the roughest bits be 70, and the smoothest be 20. I hope this rambling makes sense.

So calling all Lightwave, octane, nodes experts. Any ideas?

[juanjgon]

I have found this way:

- You have a base texture from 0 to 100%.
- Multiply it with a float texture set to 0.5 ... you now have a texture from 0 to 50%
- Use the color correct node with black level set to 0.2 ... you now have a texture from 20 to 70%

Anyway I agree that Octane needs more math nodes and a color correction tool for textures with a lot more parameters.

-Juanjo

[gordonrobb]

Bloody brilliant Juan - however.

Having looked at your solution, I think all you need is the Octane ColourCorrect Texture node. The Input Texture of that seems to have the same effect as the float Texture node, and then just adjust the Black point. Very happy with the result though

A Question however. 10% is definitely not making it go down to 0-10% brightens, is that because it is not working linearly? Similarly, .5 in the black point is taking it up a lot brighter than 50% grey. I'm getting little lost with the whole linear versus colour corrected I think.

For instance, for me to get the bump to look right in one model I'm working with, I need to adjust it to .05, which seems ridiculously low. Thoughts?

[gordonrobb]

I have found this way:

- You have a base texture from 0 to 100%.
- Multiply it with a float texture set to 0.5 ... you now have a texture from 0 to 50%
- Use the color correct node with black level set to 0.2 ... you now have a texture from 20 to 70%

Anyway I agree that Octane needs more math nodes and a color correction tool for textures with a lot more parameters.

-Juanjo

OK, I'm trying to do this again, but with now much crappier colorcorrect node. How do I adjust the black point? Aaargh!!!