I don’t know how to do this, could someone please help me?

I have a terrain I made and I want it to have a texture that is a combination of 3 tiled textures (dirt, grass and river).

I have an alphamap with 3 colors: RED = dirt, GREEN = grass, BLUE = river.

Is there a way I can make a composite material that is according to the above specs?

All help is welcome!

P.S.: If possible, I would like to be able to do this without any commercial plugins.

Thx in advance

Click me for an almost identical question.

Max 4.2 through 2012 (SP2+SAP).
XP-64 (SP2)
NVidia 9800GTX-512 (Driver 266.58).
Core 2 Quad Q6600 2.4GHz, 8Gb Ram, DX9.0c.

Well thats certainly a step in the right direction. But that would mean I would have to make a monochrome image per texture I want to sample. I guess I could export the color channels of my current image map.

Well thanks in any case!

Though if anyone has a solution without separating the color channels into separate bitmap, please let me know.

For the viewport only, FX shaders are used for this kind of setup. Here’s one in Unreal3.

For rendering in Max, you could use a Composite map in 2010 with three layers. Put the RGB map in the mask of each layer, and use Color Correction on each mask to isolate the channel you want. For example to isolate the red channel… Red=Red, Green=None, Blue=None, Saturation=-100, Brightness=50, Contrast=100. Takes like 5 minutes.