View Full Version : No alpha channel when using image map

03-20-2015, 08:29 PM
I'm not able to put text on objects without having a background coming with it. There's no alpha channel coming thru. I made a logo in AE to put on objects in LW. I made a variety of formats but all are having a black background when I use LW. I'm using an image map(not a UV) in the surface editor because it should be quick and simple. I've done it before and now I can't do it and I can't remember what I did differently. I made them in pre multiplied and straight. You can see by the different versions some have a black background and others are grey. Any suggestions?

03-21-2015, 12:40 AM
There are different ways...
I used

03-23-2015, 06:49 AM
This occurs for me too. The only solution I've found is to save the image as a .PSD.

03-23-2015, 08:47 AM
A PNG with an alpha won't automatically get clipped like you'd hope.
You'll need to plug the alpha of the PNG into the clipmap (but this will give you nasty edges I'd have thought... it only expects black or white) under nodal, or add an alpha map (black and white cutout) to the transparency texture channel.

03-23-2015, 08:57 AM
I use TGA32 (32-bit Targa) file format to do this very regularly, works all the time. I create the masked images in Corel Photo Paint instead of AE or Photoshop.

Very rarely, and I can't remember the circumstances at the moment, I've also cloned the image in the Image Editor, set the clone to Alpha Only and used it in the Transparency channel.


03-23-2015, 09:36 AM
correct method surely is through the image editor, must use alpha enabled image that actually has one but if you clone it and set the clone to alpha only and leave the original as is, you can load the original into the colour channel and the alpha only clone into the transparency or clip channel, never is a need to load a separate alpha

03-23-2015, 01:32 PM
The thing that always confuses new users about the alpha channel is that it doesn't affect the transparency of the surface, it affects the transparency of the image that is mapped onto a surface. To make this clear, you can layer many images with alpha on top of another on a single surface and if they don't cover each other completely you can see them all layered. The background would be the base color or any other thing you have under the images (a gradient, a procedural etc.)

To make the alpha of the image affect the transparency of the object you must either use the node editor to connect the color and alpha to color and transparency respectively or make a "clone" of the image and set that clone to alpha only and place that into the transparency. In regards to clip maps that others mentioned, you can also use the alpha portion of the image as a clip map, it is a binary type of transparency (no semi transparencies, it's 100% or 0% trasnparent) It renders much faster, has no problems with recursion limit, works with shadow mapped lights (regular transparency doesn't) And it also clips reflection, specular, etc. So if you are making tree leaves clip mapping is the way to go. Clip maps can now be applied in the surface editor they used to be applied in object properties prior to LW2015.