Drawing on glass

I’ve been trying to find a way to use a UV texture image to appear on a mesh object while retaining the alpha areas. In other words, the image should appear as if it’s a decal.

The actual item I’m trying to create is a transparent window with cracks in it. It would be combined with a transparent glass material tinted just enough to be detectable. I want to be able to set up the cracks as a photoshop png image with alpha. I tried a few ways last night but couldn’t get anything more than a very faded slighty green version of the image. The image is simply a pattern of white lines in the shape of a fractured window on a transparent png.

Whether it’s applied as a UV texture or a some other way, it seem like there should be a way to do this. I’ve searched forums but found nothing that clearly addresses it.

Any tips on how to achieve this would be much appreciated.

Sorry in advance as I don’t have a good enough idea on how to do it with textures and UV but usually what i do is to actually make the crack in the mesh itself. That way it is completely through the glass and refractions work the same. Whereas using a texture for a piece of thicker glass wouldn’t show the crack all the way through.

That sounds like the glass is a more complex object itself. In my case the windows are nothing more than a subdivided plane. I tried removing some faces from the center to make it look broken out, but that’s barely noticable. At least not without a lot of lighting reflections to frame it.

Take a look at this tutorial by Johnathan Williamson:

  • Bill

I tried that one. The problem there is that the image takes on the settings of the item it’s attached to, and trying to combine it with an item that’s set to almost fully transparent makes it show up as a ghost of what it should be.

I guess I’ll keep experimenting. It’s not a very important project I’m trying to do this with, but the method is something I’ll want to use again.

Post your blend here (make sure youPACK YOUR TEXTURES IN YOUR BLEND FILE). Have you set your texture to influence the alpha as well as Color ?

If I understand your problem
Here is a suggestion

  1. Cracks … Create a png image with solid and transparent portions
  2. Create a plane … with a material … alpha must be zero 0 for subsequent steps
  3. Map sure your texture mapping is generated … or generate a by uv unwrap
  4. Create texture for the material (movie or image type)… with the png … and have both color and alpha influence set to 1
  5. Choose correct mapping for texture
  6. you may need to choose premultiply in texture panel for cleaner edges

Perhaps this will give you the (partial or total ) results you seek