Jump to content

FG Mapping Issue / splotchy shadows


Recommended Posts

I realized I put this in the wrong forum earlier:


I have been trying to render an animation and have been running into an issue I am hoping someone can help me with.


I am rendering an interior animation with Mental Ray using FG and GI. The scene is lit with a daylight system and photometric can lights and finally mr Portal lights.


First I calculated the GI and all is good. I calculated the GI photon map and switched to read only.


Then I turned the photometric lights on and figured out the Final Gather solution and again...everything looked good...for the still render. I then incrementally added the FG points every 10 frames and saved the FG map. Then I turned on the mr portal lights and switched the renderer to read only for the FG map and when the first frame of the animation processed it had splotches that were not in the test renders.


Any ideas?


I wonder if I need to up the increments of my FG map? I did try every 20 frames and every 10 frames and had the same issue. I also tried ditching the mr portal lights, adding and dropping bounces to the FG --- and everything I try ends with splotches still that were not visible on the test render.


Thanks for any help or suggestions you have!



Link to comment
Share on other sites

Looks like a photon radius issue. Try reduce the photon radius, shoot more photons and turn ON Optimize for Final Gather. Increase the Max trace Depth to 100 and Max Reflection & Refractions to 50 (this will bounce the photons around more)


Leave the FG Diffuse Bounces @ 0 as any extra bounces are discarded any way.


Is the camera moving? If so rather use the "Project Points along the Camera Path" method. Although you will have to increase the FG Density to compensate of the smaller resolution from dividing the screen up.



Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...