We are starting a new animation of a car inside a tunnel. I plan to render the car and it’s headlight as a second pass. My question is how to composite only headlight’s effect to pre-rendered backgroud.
Thanks for help in advance.
If you make everything in the scene a white material and have only the headlights turned on, you’ll end up with a matte of the headlights effect on the scene. You can then use this in any comping package to add over the background or use it as a mask to colour correct the background to brighten it up and add a bit of yellow in the areas affected by the headlights.
Thanks for help.
In this case, we are going to have more control over the lighting but it doubles the render time.
Is it a good idea to comp BG and FG or do you recommend single pass?
Actually the background is not so complicated.
Are you putting a cg car into footage of a real tunnel? I’d definitely do everything as seperate passes then - it does make things more comlicated in terms of scene setup but it gives you more options later on.
Tunnel is CG.
To have more control is good but render speed has 1 priority for me. Adding lights as a second pass would take more time I guess.
Well, admittedly it wouldnt be as correct but you could render the tunnel as one pass with a cached irmap and light cache file and then do the car render as a seperate pass - might go quicker and have less flicker issues.
You are right. I didn’t think flicker issues. I’ll try separate passes way.
Thank you for all your help.
Ismail