Correct use of Ambient Occlusion

[D C]

We tend to use vray extra tex dirt map as standard, with a radius dependent on the view/scene.

 

Is there any particular AO setup you have found works well to add realism to your imagery? Maybe you bake it into the image using the GI roll out tab? If so, what settings do you find works well? If you render it out as a separate pass, what settings do you go with in the dirt map?

 

There doesn't seem to be any scientific way of using AO correctly, so it would be good to hear what solutions you have come up with!

 

[Chris MacDonald]

There is no scientifically correct way of using ambient occlusion because it isn't based in the real world. It is an effect that was created before global illumination became the norm, to show where edges and corners were, etc. Ambient occlusion is not physically correct.

 

Don't use ambient occlusion if you want things to be "correct". Vlado of chaos group hates it, and posted a link to a study where brightness samples were taken across the corners of rooms and found that there was often an increase in brightness where light was bouncing between surfaces, not a decrease.

 

This isn't to say it can't be used to creative ends, but that (I believe) wasn't your question.

 

I'll try and dig out the article if I can.

[landrvr1]

Here's a vid with some great settings I've used in the past:

 

 

Honestly, though, I stopped using AO because it's just one more thing to fiddle with in post. I agree with Vlado; with great and disciplined settings you just don't need AO unless you are creating hyper creepy horror scenes of abandoned buildings and whatnot, LOL.