Basic Comping of a Vray render

[cpnichols]

what i meant about saving time was that if you rendered a simple diffuse pass (which could easily be done in scanline as well) it doesnt take long per frame. then if you render a direct light pass without GI then that renders fast then fill light passes etc. those dont take as long to render each. however since this is GI everything needs to be rendered in 1 render which is seperated into your different passes for you to composite. as mentioned earlier it saves on having to rerender just for the sake of light tweeks. So saving in passes is not a method to speed up render times, its benifits are in its flexibility when comping.

yes... exactly. But keep in mind that if you render this straight (without splitting out the g-buffer) or render it and split out the g-buffer, it takes just as long, so that is cool. But ultimatly it gives you extra comping control.

I realuze that many of you may not have much comping experience, this may give you a taste of why it is a good thing. Comping is more than A over B. Although, if you want to tease a comper just say: "I don't know why this is so hard... it is just A over B."

[chicoone]

Thank you very much,

Ismael

[Da_elf]

I don't know why this is so hard... it is just A over B

[powerandrubber]

Good stuff, thanks for sharing! I'll be buying your lighting DVD soon.

[nvanherpt]

[quote="siliconbauhaus"]

hey, anyone got some spare time i can buy?

what did you have in mind mate?

chris.....nice thread mate

mods....shouldn't this thread be made a sticky?

just joking dude. with all the intersting stuff on the NG at the mo it would be nice to have some spare time to experiment and play around. these days time i find in short supply

[dlparisi]

Re: Basic Comping of a Vray render

You combine all of this: (Diffuse * GI) + (Diffuse * Light) + Specular + Reflection, and you get the same image that you rendered, which is this:



OK great, so you got the same thing you started with, what good is that?

When I follow your steps (in Combustion 4 with .exr's) my composited version doesn't match the RGB_Color version? The GI areas look OK but the direct light areas are much brighter. Any idea why? I'll post some samples when I get some time.

David

[cpnichols]

you taking the direct and multipling it by diffuse? Make sure your direct light is not clamped. Combustion may be clamping it by accident. Samples would help.. post diffuse, rawdirect, rawGI and the results you are getting.

[ShaunDon]

Chris, you're my hero. Of all the g-buffer compositing tuts I've looked at, this is by far the most thorough and easy to understand. I've been wanting to implement this kind of workflow into my animations, but I just haven't had the time to work through all the wisdom you've just dropped in my lap!

You are truly a kind and generous man, and I thank you!

Shaun

[cpnichols]

Chris, you're my hero. Of all the g-buffer compositing tuts I've looked at, this is by far the most thorough and easy to understand. I've been wanting to implement this kind of workflow into my animations, but I just haven't had the time to work through all the wisdom you've just dropped in my lap!

You are truly a kind and generous man, and I thank you!

Shaun

Happy to do it... give it some good solid testing beforehand. Finding the right workflow is key. Remeber to use linear color space, and unclmaped floating.

Maybe later I will do some other tips... tweaking shadows, using mattes, doing reflection in comp with the bend normal pass... hmmm... maybe another DVD.

[dlparisi]

Here's screenshots from Combustion (demo so excuse the red "X") showing the final results as well as the basic setup of the comp. You can see the difference in the sunlit areas, and "no" the image is not clamped (i.e. "clamp output" is not checked in the Color Mapping settings). Still not sure what I'm doing wrong. Chris: I pm'd you a link to the .exr files if you're interested.

[vlado]

Did you use any color mapping? If yes, then this is the reason for the mis-match between the composite and the RGB channel.

Best regards,
Vlado

[dlparisi]

It was set to Gamma Correction but both multipliers were set at 1. Would this still result in the same problem?

David

[cpnichols]

Ok looks like a LUT issue. Check in Combustion that your LUT is set to sRGB. If not, I will look into it for you later when I get home (I'm at work now). You are not using any color mapping in Vray are you? Should be set to linear 1.0/1.0

[cpnichols]

It was set to Gamma Correction but both multipliers were set at 1. Would this still result in the same problem?

David

Missed that one... yeap... gamma correction would do it. try it at linear

[trixian]

Ok looks like a LUT issue. Check in Combustion that your LUT is set to sRGB. ....snip

How does one guarantee that the settings in the lut are sRGB.
Are there any preset luts out there that can be downloaded?
And are luts generaly compatible between packages like shake and combustion, like the discreet luts are?
Also, would one be aplying the lut to the footage or just as a view-Lut?
(Not sure if this makes any sense as I'm using combustion terms in my questioning)