Quote from: metronome on April 12, 2009, 05:48:41 PM
So I drew a white line to be my trench, but what do you do with the painted shader to make it actually make a trench in the rock?
Sorry if this is really obvious I only started using terragen yesterday :p
The painted shader is black and what you draw becomes white. This way you create a mask where black = 0 and white = 1. Anything gray in between is 0-1.
You can paint in two ways: positive masking (where do I want this or that) and negative masking (where do I NOT want this or that).
Although you have painted where you wanted your trenches (=white) it is a bit easier to invert that mask. Why?
You connect the painted shader as a blendshader (blendshader is a shader which acts as a mask, in this case the painted shader) to a powerfractal for example, or any other shader capable of performing displacement. If you apply displacement the white parts of your painted mask, so the trenches, will be displaced upwards.
So the trenches are not trenches but hills/mountains or whatever you name them. You want to have the opposite! So go back to the powerfractal and select "invert blendshader".
This way everything becomes white in the mask, except for your trenches. Et voila!
To exactly reproduce your image you can better use a heightfield as displacement. Then the height of the features is exactly the same everywhere and you can give the terrain the desired size as well. Unfortunately I'm rendering right now so I can't make an example tgd for you, soI hope some of this helps at least. If you have questions feel free to ask.
Martin