Quote from: Oona on October 03, 2011, 03:15:24 PM
I saw one(1) tutorial about painting a canyon on youtube, but it doesn't explain it good enough to understand
what the person exactly did..
Can anyone help me with this?
Thank you.
I made that video on youtube and it is part of a NWDA package which offers a complete canyon.
The package contains the same Terragen file I used in that video, so without it the video is of no use to anyone. Deliberately.
However, the principle of how to paint a canyonshape is not too difficult and I'll try to explain briefly:
In your default scene go to the terrain tab, choose create terrain and then choose simple shape shader.
Inside the simple shape shader select square shape and give it whatever size you need, depending on the scale of the canyon.
Enable displacement and set the displacement factor to the value of your maximum canyon height. Say 200 for 200m maximum height.
Create a new camera and put it on the same position as your painted shader.
Set the camera altitude to something like 5-8km altitude and have it look down 90 degrees on the simple shape shader.
This is the camera you use for painting.
Make sure the preview uses this camera.
Create a paint shader and with white strokes paint where you want your canyon. For the first time, just try a simple S-shape.
Connect the paint shader to the blend shader port of the simple shape shader, as some others already pointed to.
Inside the simple shape shader make sure the blend shader is activated and that it is inverted. Very important!
Now the simple shape shader will displace the square shape 200m upwards, except where the white paint shader is, since you inverted it.
The advantage of creating a depression in a 200m tall structure is that the bottom of the canyon won't go below 0m.
You could also use a paint shader and displace that down on your default planet, but then you would need to use negative altitude things for everything which just doesn't work very nicely.
You now have an S-shaped depression which you can use as a base for your canyon.
You can play with the paint shader brush size and drop-off to control the steepness of the depression/canyon.
After you're satisfied with the shape you can compute the terrain and start adding more displacements, like redirect shaders and stretched fractals for instance to get interesting rock shapes.
"That's it" in a nutshell.
Good luck and let us know how it goes.
Cheers,
Martin