Problem making alpha planes for trees

Hello, I am trying to make a forest in Blender, using intersecting alpha planes.

But my .png’s come out weird and pixelated when I render them. Two files are posted at the end of this message to explain what I mean.

Notes: I am using Blender 2.46 on Ubuntu 8.10, Intrepid.

My process: I created the 3-D tree in ngplant and in Blender, rendered it, then took it to Gimp to cut out the background and make a transparency. Then, I pasted it back into Blender as a texture on a transparent plane (Ztransp, Map to: Color and Alpha.)

The reason why I created the tree originally in Blender rather than take a photograph of a real tree is because my tree is an ALIEN tree; it is supposed to be blue.

Why am I getting this pixelation?

Can anybody help? Could it be a bug? Thanks for your help, it would be greatly appreciated.


In Blender you can set the output format to RGBA instead of RGB. Save to tga. eg - skip the Gimp step entirely.

I had this problem once, and it turned out that I actually had some alpha on areas where the texture didn’t reach, and because I had my plane set to clip alpha, it made these white areas visible. I fixed it by going into the uv/image editor and clicking the alpha only button. By switching back and forth between regular view and alpha only, I could pinpoint the problem areas and correct them with the texture paint tool.

I hope this helps.:slight_smile:

Thank you very much for your help. Playing around with the Render buttons worked. I saw on another forum that the best is to use Png and RGBA, with “key” button turned on for rendering. But your suggestions got me thinking in the right direction. It cleaned up all the pixelation around the tree.

But now I have another problem.

I placed the image into the plane, duplicated it, and rotated it 90 degrees as it said in a tutorial on faking 3-D trees. Here’s my problem: When I duplicate these intersecting planes and scatter them around in the camera (I’m trying to make a forest), it only renders the one tree, and can’t see the other trees behind it. I used Ztransp and set the Map To tab to Col and Alpha, set the slider to zero. I set the Map Input to Win, and made it shadeless, as mentioned in many tutorials about plant making.

And then this is problem #2: I noticed that the tree gets cut off in the plane depending on where the camera is. I need the tree to stay a constant, set size so that it always stays in the plane.

The reason why is because in animation I want the camera angle to change, showing the point of view of an alien frog character jumping up from between trees (showing the forest canopy horizon) and then falling back down below the horizon of the trees.

I want to get a parallax effect with multiple intersecting planes.

Here is the tuturial I originally used:

I want the trees to stay fixed in the planes, in other words, so that you can see thru the planes and the planes not casting shadow, JUST the trees.

Any suggestions?

Your feedback is greatly appreciated.

Step 4d says—>. Click the map input tab and select the UV button.

If you don’t want to use UV, Orco might be worth a shot.

Press the PreMul button on the texture that contains the tree map.