Vraydirt dont work as expected.

[correntes]

Hello,

Lets say I have a stone slab with 50cm x 50cm with 2cm thickness.

When I apply vraydirt with a radius higher than the thickness of the object, the Occluded color starts to contaminating the whole object.

3rd party plugin richdirt works without problem in this case scenario.


Any workaround ?

Thanks

[Morbid Angel]

please provide example scene. Is your stone slab sitting on another piece of geo? or is it on its own?

[correntes]

Sure

One slab of 50x50x2cm


The first image have a radius of 1 cm, works as expected.

The second have a radius of 3 cm - fail

If I use a radius of 5 cm the slab is completely red.


For what i know, richdirt calculates the dirt fine.

[joconnell]

Yeah, richdirt has a special method for considering thin objects which gets around this. Vray dirt is doing exactly what it's supposed to and its working as expected with the two flat faces of the slab being within the radius you've set in the AO. It's working but it's unfortunately just not the result you want :/

[correntes]

Working as expected is real subjective. What use does this effect have ? This seems a big handicap...

So I'm forced to use richdirt ?

[joconnell]

Loads of uses with most people using it to add a certain amount of sculpting back in to scenes or objects that get washed out by very airy looking global illumination or use smaller radius values for more subtle effects.

Ambient occlusion is kind of a simple technique and it's doing exactly what it's supposed to here, rich dirt is a bit more complex and has a lot more control and features to get around this problem. It's well worth it if you're doing a lot of archvis or environment stuff too - well worth the price of purchase!