GI Solution

[yourfather]

Hi,

 

im trying to figure out what a good GI solution looks like.

 

If i render with just GI, should i try and get an image that has lots of small photon samples or should i use large photon samples to blend the photons together.

 

Of course i will use FG at the end to clean it all up.

[Matt McDonald]

A good GI solution typically looks like smoke (which is sort of ironic because a bad FG solution looks like smoke). You want lots of smallish photons evenly distributed. If your photons are too large you can run into issues where different faces of the same wall or object have the same amount of illumination when they should not.

[yourfather]

Hi Matt, thank you.

 

If i have lots of small dots, there harder to blend together to make it look like "smoke". My maximum sampling radius is 8" and if its lower, i get smaller dots but they dont blend.

[Matt McDonald]

have you tried increasing the average number of photons per light in the rendering dialog?

[yourfather]

Im actually manually controlling the light photons.

 

My sun in generating 400000 photons and my sky portal is generating 400000 photons.

My GI is using 8000 photons per sample and has a maximum radius of 8" to smooth it all out.

[Matt McDonald]

Are you only lighting using the daylight system + sky portals or do you have lights as well? You can try increasing the photons locally to each light source but I don't see a problem doing so globally from the render dialog. I've run into issues where the sun gobbles up all the scene photons but that is solved by tweaking the gi photon multiplier on the light.

[yourfather]

Thank you Matt.

 

Its really tough talking about stuff like this without posting pictures.

 

Im guessing my GI is ok. When you say there should be lots of little photons all over, that makes sense. But then when you say it should look like smoke. Thats confusing because the scene cant look like little photons all over and at the same time look like smoke.

 

Im going to have to wait till i can actually post some pictures to help you guys help me.

 

Have a good New Year!