Making a shape with an alpha channel

Support Modeling
1

Hi All,

I was wondering if it is possible to place an image with an alpha channel onto a plane then use that alpha channel to extrude out the shape of the alpha.

Thanks,
Stephen

2

Not possible, I think.
But you could create a path or bezier curve from the alpha channel in Gimp or Photoshop, export the vector and import the path to Blender. Convert to mesh and you can extrude that…

3

You can use a texture as a displacement map. Create a black and white image. White beign the area you want to extrude. In edit mode Subdevide your plain a few times WKEY>Subdivide, add a subsurf modifier F9 >Modifiers Panel. Now add your image to the materal and on the Shading (F5)>MapTo Panel turn Col off, move the Nor slider to zero and turn Disp on, set the Disp slider to the desired displacement. Render the picture to see the dispalcement. Also not that shades of gray in the image can also be used to control the amount of displacement. So 50% Gray will displace 1/2 as much as white.

Here is an example: (Click on images for better view)

dot_displacement.jpg640×512 12.3 KB

and here is an example using a complex image for displacement with very hi subdivide and subsurf.

Stone_Block2.jpg994×940 103 KB

4

Since ReeVee already showed the “displacement” way here’s another one that applies the elevation manually:

Advanced Mesh Modelling: Noise

I don’t know if you can use the alpha channel of an image as a source of the displacement, but you can still make it a seperate image so this is no real problem I think.

EDIT: And the reverse way: geometry to displacement-image

Werner

PS: Just in case: “Alpha” doesn’t normally mean a seperate black/white image … it normally refers to the Alpha channel (transparency) of a texture or model.

5

Just remember, when you use Displacement you will see the effect ONLY when you render the object. No manual mesh editing in Blender or anything like that.
It’s obvious but I just wanted to make sure…

In my opinion that would be a good way to add final details to a mesh, but not really a good idea to actually start a model with. I’d suggest you try grafix’s tip first, as it seems like a very convenient way to achieve your goal.