What max distance do you use for ambient occlusion?

[robkar97]

I really like the nice renderings you get with AO at a very low cost in render time. I tend to crank up the max distance to 2-3 meters and do a separate AO pass for compositing.

 

However, I know you should only use AO to enhance *details*, at say 100 mm level or below.

 

So, what max distance do you guys use?

 

I you keep it in the 10-100 mm level, how do you get that nice photorealism without extreme render times?

 

Cheers,

Robert

[Justin Hunt]

It all depends on where its being used, the proximity of surrounding objects and the complexity of detail on the object itself

 

ie if its a large wall then a larger AO radius is good but it it a bunch of closley packed batterns then a smaller AO is needed.

 

There is no hard and fast rules, what works here may not work there.

 

AO is very powerful, I have used it in many ways it wasnt intended. Such as dropping it into the self illumination slot to simulate skylight without there being any light at all. Renders really fast. Other times I've used it to create sharp to glossy reflection by dropping it into the reflection slot of a standard material.

 

Once you understand the AO concept in how it works you'll see how simply powerful it really is.

 

JHV

[armark]

Sorry Justin

How do you do that? its great.

Do you save AO pass like .tga, jpg, etc.

Tanks.

[Justin Hunt]

For the self illumintaion, just drop the AO shader into the self illumination slot of your material, and render with out any skylight, FG or GI. Smaller illumination values work better. Still have a sun for the direct light and shadows.

 

For the glossies, this method is used if you arent using the A&D shader. Use a standard max shader, drop an AO into the reflection slot, in the dark colour put a Lume Metal shader and in the light slot a Lume Metal shader with the blurry reflections set. Depending on the AO samples and distance the sharp to glossie is controlled. NOTE higher AO samples will be needed for smoother results, thus can be quite slow to render.

 

If you are using the A&D shader then set the high detail distance in the Fast Interpolate panel. Reflection within the max distance will blend from sharp to glossy.

 

JHV

[armark]

Tanks again.

Very useful information.

[hendrix2430]

Is there a way to regulate the amount of ambient occlusion?

 

Samples or max distance?

 

Do you usually have it on when using the Arch and Design shader?

 

For instance: how do I proceed if I want a teeny bit of Occlusion going on, just to add slightly more detail to corners. For instance I have the bottom corner of a lightwell that's being washed out too much. How do I make that corner a bit more visible with AO?

Edited June 17, 2008 by hendrix2430
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