Ambient Occlusion Pass

[Guest]

Apologies if this has been cleared up already but there seems to be more than one way to do the same thing. I just wanted to know which is the most effective.

1) Add a vray dirt material to the override in global switches and turn GI off.
Do I need to turn off my camera exposure and set my environment to white if i use this method?

2) Add a VrayExtraTex as a render element and use a vray dirt map as the texture.
Do I need to turn off my camera exposure and set my environment to white if i use this method as well? I have read that this method render slower than the above.

There is also an ambient occlusion setting in the GI rollout. How does this work? Doe it replace both the above methods?

Thanks!

[Guest]

Here is an AO pass created using method 2. Doesn't look right to me :/

[squeakybadger]

for method 2, you just need to change the radius for the vraydirt material.

I use around 800 to give it a nice thickness.

[Guest]

So the attached image is correct just the radius is not enough?

I thought it was supposed to look more like this http://scottdewoody.com/images/tutorials/occ10a.jpg

[squeakybadger]

So the attached image is correct just the radius is not enough?

I thought it was supposed to look more like this http://scottdewoody.com/images/tutorials/occ10a.jpg

This is a radius of 800mm, but you might want to go higher/lower depending on the scene. Also play with the subdivisions for the vraydirt, as this one was done with 16, but more will equal smoother dirt.

[LarsSonparsson]

If you scene is in right scale, I'd try something like 100-200 cm for the radius. That will give you results like in your example picture.
You should also increase dirt samples to 24 or 32 to get clean ao pass.

[Guest]

ah cool thanks