how to match composition and beauty?

[wannabeartist]

Hi,

I've been trying to learn the Composite (Toxik) application that comes with Max.

Despite various tutorials, there's one basic thing that I haven't seen done anywhere - how do you (or can you?) create a composition of the render elements that matches 100% to what you get if you render the image in Max and let mr Photographic exposure control tone-map it?

I'm usually quite pleased with what a simple render with exposure control gives, but it would be nice to be able to tweak it too. The trouble is, so far I haven't been able to recreate a completely similar image in Composite.


I've been trying to use the simple formula from the help:

"Beauty = Output Diffuse Direct Illumination + Output Diffuse Indirect Illumination + Output Specular + Output Reflections + Output Transparency + Output Translucency + Self Illumination"

and my test scene is using A&D materials exclusively. In Composite I put those together using blend&comp in add mode and I have tried using the Photolab node to tone-map it, but it seems quite impossible to match it with the simple render.

So any tips for this?

Thanks!

[jb_alvarado]

I think the best way is, to render with output gamma 1 (apply it in comp) and don't use exposure control.

[wannabeartist]

Well,

yes, but that doesn't really do the trick yet. The trouble is that when you put your passes together and gamma correct the result it's not quite the same as rendering without passes and letting exposure control tone-map the image. It's close, but not exactly the same.

Not that it would be that important to match it anyway

[Jenni722]

Yes, matching the results of the mr Photographic Exposure control is tougher than it seems it should be; a "Photographic Exposure" node in Composite would be nice. Are you rendering to EXR?

There certainly is more going on 'under the hood' with the mr Photographic control than simple compositing, as you have controls for a variety of settings: Highlights, Midtones, Shadows, Saturation, Whitepoint, Vignetting.

The CC Basics node gives you Shadow, Midtone and Highlight adjustments.

The Glow node can give you Highlights; set the Threshold to something close to .95 and adjust the Gain.

The Remap Color node can do some interesting things with the final image in Linear mode, and with the output of the HDR/EXR images with the EXRDisplay mode. Like all of these nodes it takes playing with the settings and getting your head around what they are doing.

You can try the sRGB to bring the exposure down.

Because Composite is infinitely variable getting the same results as the Beauty pass will be tough, no doubt.

Jenni

[wannabeartist]

Maybe such a node is available in the future

I render mainly in EXR now, but I'm still not very confident with using Composite, so for things that really need to get done fast, I just render in PNG and use exposure control like before.

Thanks for tips on the nodes. I will try to make more use of them, while I get more familiar with Composite. So far I've been mainly using the Photo Lab node to Gamma correct the exr-images, then outputting to something like png.

With 32-bit images, I still have some issues with bright areas that sometimes cause aliasing. This is usually my main reason for falling back to "old school" png-renderings and using exposure control. I have tried several workflows to fix that, using luma keying, lens blurs and just Glow, but I'm not quite satisfied with the results yet.

Why it happens, is well explained by Master Zap in this old thread, but there still doesn't seem to be a very straight forward way to fix that.