Creating dirt on concrete wall.

[TRI-FI]

Hello, I am a beginner in arch viz. I would want to know how to apply dirt features on concrete texture using mental ray for 3ds max. Thank you.

[Matt McDonald]

The cheap way would be to paint dirt onto you textures in photoshop or to composite a dirt texture over the top of your diffuse texture. Or, there is this: http://www.enrichpro.com/en/richdirt/index.html

[Chris MacDonald]

There are a number of ways to do it (without plugins), and it depends if you want to spend some time on it or not...

 

The simple way would be to UVunwrap your surface and paint dirt on in photoshop, then stick this in a composite map over your concrete diffuse and set the blending mode to multiply.

 

Alternatively you can do something similar but use a blend material and the same uvunwrap to blend between a clean concrete material and a dirty one, which will give you the ability to tweak the materials independently - if you wanted the dirty parts to look damp/wet for example.

 

Don't forget to set your uvunwrap channel to something different to your base/diffuse uv channel (defaults to 1).

[unrinoceronte]

Hi Chris, i am interested in this also, altough i use Vray... I kind of sort of understood your procedure, but do you know of a tutorial that explains and shows this in detail? Or under what keywords should i google it for? I have never done Uvunwrap before...

 

I would like to learn this with a manual method and not use plugins...

[Nic H]

another vote for learning vray blend...

i dont think you need a dedicated plug in for this

[Chris MacDonald]

UV unwrapping is a way of telling your 3d software "this part of the texture needs to be displayed on this part of the geometry", and it's the most widely used way of doing such a task, although PTex appears to be the future and looks very promising indeed, but isn't as widely used outside of large studios.

 

[edit] I'll make a video when I'm not at work. In the mean time, just a quick tutorial...

 

Select your wall (or whatever you want to do) and add a uvwunwrap modifier on it. Then enter polygon selection (the red square, same as in an edit poly) select the face(s) you wish to apply dirt on and click open in UV editor.

 

When the new window opens, click "mapping/flatten mapping/ok", and provided you're giving it fairly simple geometry to work with you should see the shapes flattened in front of you. This is your UV template that you need to render out (tools/render uvw template) and take into photoshop to paint your dirt/mask onto. It will render in the max framebuffer and you just need to save it.

 

The best thing to do once you think you've painted it is to apply it as a diffuse and set it to display in the viewport to check that it is all correct. Don't skip this step, as the number of times I've painted UV maps and they've been upside down I can't even begin to count. If you have a large number of faces you're unwrapping it might be best to number each face in photoshop and save the file, then view it in the viewport - this way you'll see each face numbered in the viewport with your new texture.

 

Sorry if large swathes of this don't make sense, I'm writing it at breakneck speed here haha.

Edited October 1, 2013 by Macker