Newbie: alpha mask ?


(numaQ) #1

Hello again…

I have a jpeg picture of a tree with a black baground.
Then I put this picture on a plane facing the camera.
All I want now is the to make the black background transparent
to see only the tree.

I ve tried “face select” + “paint buttons” and switch between opaque, add and alpha.

With “add” the plane seems to bee transparent but the texture too !


(Peter) #2

Yes, the add botton makes the hole jpg image transparent, more or less. If you want more control over the transparent part you should make an targa image of your tree with a mask that defines what should be transparent. Then you use the alpha button.


(numaQ) #3

Ok, I’ve made an alpha mask of my picture.
The tree is now white, and the background is black.
Can I apply the previous texture (the “green” tree with black background) and the new alpha mask on the plane ?

Or do I have to make another picture with an tranparent background ?

The targa image must be 8/16 ore 32 pixel deep ?


(numaQ) #4

In my previous post the last question is:

“The targa picture must be 8/16 or 32 BITS/pixel deep ?”


(Doc Holiday) #5

TGA’s must have 32bit to use them in Blender. If You want to keep Youre Image in JPG Format, have a look at my Post here:

http://www.elysiun.com/forum/viewtopic.php?t=7551&sid=9f97a4b3e9d240122b15f78b5f607cd4

Doc


(kEinStein) #6

Yes, you should make a new picture with a transparent background. UV-map the image and activate the alpha button in the paint buttons menu. Yet it should be transparent. Semitransparency is also possible if you have areas in the alpha layer that only have e.g. 50% opacity. Check the docu of your image manipulation programm to know how to create targas with an alpha layer.

Blender will transform it to a 8bit color depth. The best would be if you reduce the color. Then you have not only more control over the color, it also is faster.

btw.: 8bit color depth sucks!