Color_Curve???

[shushens]

If you say so, Hirazi

I have another question, which is not exclusively about skin shading, but about any colour correction in general.

Clipboard01.jpg

Say I want to colour correct an image with the colour curve. Now, here, unlike Photoshop, there is no master curve. No matter how precise you are, it is almost impossible to draw 3 curves perfectly identical. I tried to link them with expressions, but since the curve does not return any definite numeric value, it is not working.

How can I make any 2 curves automatically copy the 3rd curve, so that I have to edit only one and it is reflected in R,G, and B all three?

There is one thing I can do to avoid this, which is importing the clip to FxTree and using the colour correction tools there.
But naturally, if I do that, the change will not be propagated when I export the shader compound or save it with a model.

So I was wondering if there is a smart way of doing this within the RenderTree.

[Hirazi Blue]

Seems like you uncovered yet another bug in Softimage 2011...
The "animation divots" would imply the possibility to set expressions,
but a quick test seems to show that they just simply do not function...

Ah well, welcome to the wonderful world of Softimage 2011...

Meanwhile I'd have to think about a practical workaround, I'll get back to you...

[shushens]

Always happy to be useful to the Softimage community
No matter how many bugs I find, my opinions will always be totally biased in favour of Softimage

[Hirazi Blue]

Okay, the reason you can't link two fcurves directly has something to do with the way they are stored... I just got the value of one of those fcurves by script, but it only returns "fcurve" and I haven't had time to look into the way these are stored...

The fact however that the "animation divots" seem to be only good for creating the red warning sign "wrong input specified" still remains a puzzle... ;)

[Mathaeus]

Hi there,

you can use render tree like one in image. Just don't forget, once you got your image in render tree, it's in floating point, regardless of original format, so you can set colors to outside of 0-1 range. For example, you can create a 'fake HDRI' from 8-bit image. Also, Photoshop, due to it's nature, can afford some more sophisticated, but also expensive calculations - one example of that is a famous Photoshop's 'Soft Light' blending mode, which is completely different than one with same name in Softimage. On the other side, modern shaders can use additional calculations too, instead of simple additive or multiply.
All in all, you can't expect exactly the same result in both applications.

About setting expressions on animation divot for *color* input, this doesn't work in XSI for a long time. It's not a bug, it's just a "group" of three of four scalars, grouped together for easier keying, I suppose. For setting expression there, you can use three or four "Scalar_savestate" nodes, set expression on each one, then combine them with RGBA_combine node...

In your skin shading workflow, you used additive mode for blending layers. Mi_sss_skin is using "screen" by it's default. "Screen" usually means something like
1 - (( 1 - ColorA )*( 1 - ColorB )), and produces 'soft' look, it's hard to overburn image when using this mode. Result of blending won't go over 1 (if all inputs are inside 0-1), but it affects the blending at low values as well.

Screenshot of rendertree

Cheers