vray dirt

[cr8 pixel]

can anyone help me with vray dirt?

[Tommy L]

What do you want to do with it? Have you tried using it?

[cr8 pixel]

i ve been trying to know how to use it, do i use it as diffuse or bump or ...

thanks you

[Tommy L]

Well, its a shader, you can use it however you like. What are you trying to acheive?

[cr8 pixel]

i was making a test render, its an old house, i used stone material (lebanese white vernacular stone), i made the material on photoshop : diffuse, bump, and displacement maps,

after rendering i thaugh it was better if there was dirt on the stones, not only dirt but also maybe green grass... in the cracks

[Tommy L]

Vray dirt is a map that gives control over texturing the AO (ambient occlusion). If you read up on AO first, you'll understand the controls in the map. If your stones are geometry, then the dirt-map will recognise where the cracks are.

[cr8 pixel]

ok ill read about it, and i think the problem is that the stones are not geometry, they just are a map, on a box, thanks a lot for ur help man

[pailhead]

Vray dirt is not an instant make-it-look-cool function, it's just a procedural map/shader whatever you want to call it with a specific function. Take a look at the help for examples. It should be used in conjunction with other textures to make it work right

[batteryoperatedlettuce]

One use is to make a "dirt pass" and multiply it with the image in compositing software, like you would for an Ambient Occlusion material in mental ray. This will bring out contrast in edges, cracks and dark corners of your model where the faces meet.

 

Try this:

 

- make a new vray light material and set the multiply to 1

- put vrayDirt in the Texmap slot

 

-go to the global switches in Vray

--switch on "use override material" and drag the new material into the slot

--turn off GI

--turn off all lights

--turn off exposure on your vray camera if you are using one

 

-render using adaptive QMC

 

(This should render fairly fast depending on the amount of subdivisions you used in the vray dirt.)

 

-In photoshop or some other layer based compositing software, place the vray dirt pass above your original rendering and set blending to multiply.

 

-rub out the bits you don't like.

 

This also works if you put a vrayEdgeTex in the Texmap slot of the light material - another interesting pass for later compositing.

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...cheers for that lele

[alexthg]

I think the name 'vraydirt' causes misunderstanding. It's not a 'dirt' texture material... it's just a way to achieve ambient occlusion with vray.

[Tommy L]

I think the name 'vraydirt' causes misunderstanding. It's not a 'dirt' texture material... it's just a way to achieve ambient occlusion with vray.

 

Well thats not really true. It gives you control over the parameters within the occluded/un-occluded areas. An ambient occlusion pass is built in to the render engine. Vray dirt kind of allows access to modifying the treatment of the AO by assigning parameters to such things as the spread and texture. By its very nature, its effect is stronger in crevices, so can be made to look like dirt.

[Tim Saunders]

Your a smart one Tom. The idea that vray dirt is an ambient occlusion is probably one of the larger missunderstandings in the vray group. I think it's because of the use of the word "occluded" color. It's just a map type, like checker with max.

[Tommy L]

Your a smart one Tom.

 

Now thats a post. Keep 'em coming pal.

[batteryoperatedlettuce]

Your a smart one Tom. The idea that vray dirt is an ambient occlusion is probably one of the larger missunderstandings in the vray group. I think it's because of the use of the word "occluded" color. It's just a map type, like checker with max.

 

yes, or the misconception could also stem from documentation like this:

 

The VRayDirt is a texture map that can be used to simulate a variety of effects, for example dirt around the crevices of an object, or to produce an ambient occlusion pass.