Combining Alpha Materials

Im trying to create a low poly street scene with roads, pavements grassed areas… I have created alpha images of each element which i have added onto a plane, when i lay the places on top of each other the plane outline becomes viable breaking the illusion.
Now i am trying to combine all alpha images into one plane but when I use the mixed shader onto 2 alpha images the solid areas go transparent (red and green shapes are 2 alpha files, cube is behide showing transparent material which i dont want!).
Can anyone help with the nodes or discribe a better way of doing this?

So what is the result you are after? Do you want a solid red colour in front of a solid yellow? Do you want the colours to mix together (and be solid)?

humm… not quite understanding what you want to do… :confused:
but why not mixing the two diffuse shaders, with the fact of one of the masks, and then mix the result with the transparent, add both masks with math, and use it as a factor for the last mixer?

The end result I’m after is to have a solid road shape that I can add a texture to, then do the same with pavements and grass areas.
This is what happened when I used 3 transparent planes overlaid each other, the transparent areas start showing

[ATTACH=CONFIG]346481[/ATTACH]

As long as the street and the land around it are separate objects, you can use this technique.

Also, if you want more detail, take a look at The Secrets of Realistic Texturing. Near the end, Andrew shows how you can build a complete street from one section and even have it go around a corner.

And, BTW, if you don’t have (and can’t afford) Crazy Bump, MindTex does the same job for only $17 U.S. You may have to invert the maps, though. I’ve only used it a couple of times so far and it seems the normal maps, especially, look wrong unless they’re inverted.

Andrew doeshave a great library of tutorials, I have been tuned into his site Guru for awhile.
I have used the bump mapping in past project andalpha mapping but never done several alpha images on the same object

This is a node group where 3 different alpha images are combined into one. It can be used as shadeless material or transparent which then overlays image on plane below. http://www.pasteall.org/pic/show.php?id=80457
Is this something like you need? Do you want to “paint” underlying image using such transparent planes? Shouldn’t it be done in image paint program? Blender’s material or rather such image combining has certain issues which are easier to deal using image editing.

Edit: check if your images you map on planes have one pixel 100% transparency all the way around. Streaks might be caused by this. (Wild guess…)

Still having trouble with the colours not being solid and the transparent areas going grey, Ive not used the nodes to this extent before


The reason you are getting see through sections is because you are combining the materials after you have already added transparency into them.

For example, one mask will set (some) part of an image as transparent. If that same part of the other mask is meant to be visible, when you mix them both together, it will be a half mix of transparent/diffuse.

The method that Secrop suggested would work for what you are trying to do. Where you stack up the images, mixing it with a transparent shader at the very end.


Or, as Eppo suggested, why not combine them all manually first in an image manipulation program?

Try this setup instead:


Its so obvious when you see it set out like that.

Thanks for all your help

if it worked, then all you need to do is:
http://www.blenderartists.org/forum/showthread.php?322623-How-to-ask-questions-effectively-on-blenderartists-org-support-forum&p=2626099&viewfull=1#post2626099

:wink: