Combining of texture and map

Support Basics & Interface
1

Hi,

I am trying to master the combining of image texture, alpha map and bump map. In this exemple I am trying to create a black asphalt street with brown tire tread. Here is my layers:

  • Black material
  • Cloud texture
  • Tire mark (A JPG with white backgroung with brown tire track.)
  • Tire mark alpha (A JPG with white background and black where the tire
    tracks sould be.)
  • Tire Mark bump (A JPG with black backgroung and white where the track
    should be.)

Can somebody look at this file and tell me what i am doing wrong.
I read many tutorial individually i can do it but i cant combine.

home.istar.ca/~coulombe/texturetest.blend

Thanks

Kai

2

Hello, Kai!

The problem lies in your interpretation of where the “alpha” for the tire treads is figured out. In the way you have it, it appears that you want your tire tread alpha to make the road transparent, when in fact you just want the tire non-image area transparent.

This is handled in the Texture screen: “calc alpha” is needed if your image does not have an alpha channel included (TGA and PNG only), “use alpha” if it does have an alpha channel, and “negative” if the alpha (either calculated or existing) is backwards from what Blender expects.

In your case, deleting the “alpha” texture channel, and selecting “calc alpha” and “netagive” in the color Tire Mark .jpg file does the trick quite well.

Here’s a corrected .blend file. Hope this helps!

texturetest.blend

-Bischofftep

3

If you give me your email I’ll send you my 3 different renditions. If you don’t want to post it put it in my PM.

Bumpmaps: It’s the white that gets raised so if you want the tire tracks to be depressed into the road the tracks should be white.

Normals: By using the normals options you can use any texture to behave as a bumpmap. So I ended up using only 2 textures, asphalt and tiretrac.

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4

Hey Bischofftep and flight,

Thanks for trying to help me!

I was looking at the version Bischofftep modified and it work in this case that the same image with the tire tracks can be use as alpha. But i want to learn to have a alpha image affect the texture image in a scenario where you could not use the image as its own alpha. Those this make any sence. :smiley:

My email is [email protected]

Kai

5

Your only mistake with the use of alpha was that the images of the brown tire tracks were on a white background. That white interferred with with the rest of the image. Had you used an image with only the tire tracks (and the background transparent) it would have been fine.
Bischofftep explained it as much as can be explained.

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