Normal Mapping Question for the vets

Billz

Hey guys, I have a somewhat noob-esque question for ya.

Am I able to use more than one normal map per object in 3ds Max? Basically, what I'm doing right now is modelling a high poly pineapple hand grenade, which I'll by using to bake the extrusions onto my low poly mess. Then I was planning on using Crazybump or nDo to create normals from some scratched metal textures I've taken pictures of.

Is it just a matter of adding another normal bump in the bump section of the material? Thanks guys, I appreciate any insight you've got!

Racer445

combine them in photoshop? just paste the map you made in crazybump/ndo as a new layer above your baked normals, set blending mode to overlay, then right click on the layer, select "blending options" and under "advanced blending" just untick the blue channel. play with the layer opacity to make it more or less bumpy.

Billz

Ya was thinking about doing it like that, wasnt sure if there was a better way to do it.(not to say that way isnt good just wondering if max handled it differently) Thanks though, if it works it works!

Bal

It's usually cheaper to just combine them in photoshop.
If you really wanted to combine two normal maps otherwise (for instance, if they are using different UV channels, like a detail map maybe), you'd have to do it via shader. It's probably doable in 3dsmax 2011's new nodal material editor (not sure, haven't looked into it yet), stuff like ShaderFX, or in a game engine like UDK.

Billz

Ya I see what you mean Bal. Definitely would be more efficient. I know that when you add a normal bump in max it gives you an option for additional bump, but havent tried that yet. Always though it refered to a basic bump map. Will probably go the PS route. Thanks guys!

Eric Chadwick

Double normal maps in a shader usually means more render passes (lighting has to be calculated twice), so it's done rarely, never for a small prop.

Some stuff here about pre-blending the normal maps together into one...
http://wiki.polycount.com/NormalMap#Blending_Normal_Maps_Together

Billz

Thanks Eric, that page just got bookmarked!

Silix

you can actually have the same layering functionality as photoshop in max for your shader using the composite map, and alot quicker.

1. assign the base normal to layer 1 in the composite map
2. create a new layer and assign your map you want to overlay on the base map to layer 2 in the composite map
3. switch the blending mode of layer 2 to overlay and your all set

i use the 2011 material editor which makes it all easier but the process is exactly the same for the compact one

i use this method for AO maps cause it takes a little time to open photoshop on my computer with max open, then also if i'm using a standard shader i can use max's "ActiveShade" feature to tweak my AO map in real time.