Multiple bump maps

Matt_Castle

Not a vitally important question, as I can manage it via layering files Photoshop/GIMP if necessary, but with all the various tricks out there to have surfaces fade between materials, have different materials on each side, etc, is there any way to make a surface accept two bump maps?

Although the recently released GenNext tool is great when it comes to transfering SD morphs, I'm looking at ways to try to retain HD data in the transfer, and while I'm entirely capable of using BLender to convert this to a displacement map, I want to partially apply the results as a bump map (in order to reduce the displacement strength and reduce the number of clipping issues that come from using that rather than a true HD morph), but obviously most of these models already have bump maps.

Naturally, being able to assign two bump maps rather than having to merge them would save a lot of time and make tweaking parameters rather quicker and easier.

 

JonnyRay

You could do this one of two ways.

The easiest would be on the map in the bump channel, choose the Layered Image Editor and combine the two bump maps there by adjusting the "opacity" levels between them.

The other way would be to use the Shader Mixer to build a customized shader which would accept two maps and some sort of a blending slider. Use the slider as a mulplier against the two maps before adding them together, then feed the results of that into the bump channel.

Karen

I know this is an old thread, but maybe you could help. Do you know where I could learn how to build such a shader? Not for two bump maps but for normal maps.

 

Matt_Castle

Karen said:

I know this is an old thread, but maybe you could help. Do you know where I could learn how to build such a shader? Not for two bump maps but for normal maps.

I did, eventually, build a modified version of the Iray Uber shader where you could plug in two bump or normal maps in any combination; you can study the 4-layer Iray Uber shader in the shader Mixer to see how it allows layers to have either a bump or a normal map, and apply the same principles back onto the standard Iray Uber shader to let you tell Iray which map types they are.