How can I create a jagged alpha map to make a plane like it has been ripped off from a piece of paper.
I think a noise of some sort (I haven’t had time to experiment but if I added a ‘squashed’ ramp to a wispy noise - can’t remember if its a type of Voronoi or sumpin’) but the problem is how to blend it away at the edges.
tair a peace pf paper, photograph it and use it as a texture?
I’ve been thinking about this too. One thing to keep in mind is that when paper rips, it often divides into layers, creating extremely thin places where more light comes through. Also, it has fibers sticking out along the side almost like fuzz. This would be very difficult to do without ‘cheating’ like Hessiess suggested…
Maybe create a uv mapped image, and use the erase alpha paint feature with different procedural brushes to paint the layers of tearing - then apply it to the material to affect alpha… then you could use procedural, but make a specific texture for it.
If you need the other side of the tear, then resave the image as another name and then unwrap the other part, rotate the unwrap and flip it…
but the problem is how to blend it away at the edges.
Are you asking how to get it to dissappear? Set up your texture as black and white, and then set it to affect alpha, and enable z trans or turn on ray transparency…
SSS may or may not help the effect (not sure if it works on planes cuz I don’t really know how to use it) but I do know that you can use textures to define the scatter level.
http://wiki.blender.org/index.php/Manual/Subsurface_Scattering
I’d go with:
Scan a ripped piece of paper with teh scanner open
In the gimp, eraze the black background, andreplace with transparancy, save as a png.