Is it possible to bake normal maps into diffuse maps?

Exroath

Im entering a mini contest tomorrow, They have asked for something I find odd.

They want to see a high to low poly process yet they are only allowing a diffuse map to be used?

Is there a workflow I can keep as much detail as possible and bake it into a diffuse map?

EarthQuake

Generally for that sort of thing you would bake a directional light map (some might refer to it as a point light map) from the highpoly down to the low to use as your base lighting for your diffuse texture.

That is a bit odd though, that a high poly would be required for a contest without normal maps.

Try this thread: http://www.polycount.com/forum/showthread.php?t=101000

[HP]

Yeah, bit weird.

But still possible, grab your normal map, go to channels, select and copy the green channel. Now paste this onto a layer on top of your diffuse map, set it to Overlay and bring the opacity to around 20%, or tweak it to whatever looks best.

MM

[HP] wrote: »

Yeah, bit weird.

But still possible, grab your normal map, go to channels, select and copy the green channel. Now paste this onto a layer on top of your diffuse map, set it to Overlay and bring the opacity to around 20%, or tweak it to whatever looks best.

if you are going to use green channel of normal map, i suggest baking an object/world space normal map for that since it is pure highpoly information rather than tangent space information which can have weird triangulation shading due to vertex normal.

but to address your main question, you can add highpoly information like ambient occlusion, curvature map and cavity map. to go even further you can try to bake some sort of GI bounce map in your choice of application and finally you can bake in some image based light information into the model or combine the IBL lighting with GI to get a more integrated result.

EarthQuake

Overlaying green channel of a tangent space normal map doesn't make any sense, tangent space normal content depends on lowpoly mesh normals, uv direction, etc. So you're going to bake in smoothing errors and seams if you do that.

Like MM says, if you want to pull content out of a NM, it should be object space, as object space has absolute, not relative values.

Exroath

Many many thanks on this

Joopson

In xnormal, there's a map called PRTpn. What this map is, is directional lighting and shadowing, with each channel in the map being from a different direction. It saves out two maps. PRTp and PRTn. You can take the green channel from one of those; it should be lighting directly from above. You can multiply it, or whatever, over the texture, and get some really cool results.


I didn't make the character below, but he used this map as an overlay in the way I mentioned:


As you can see, it retains a lot of depth, even in a flat lighting environment.
Super useful map.

Fingus

Aw shucks, that's my guy. :>

Here's some detail on the layer setup.



Not sure exactly why I used both a WSN and pRTP with different blending modes. The way I usually do it now is roughly this:

Cavity/Curvature - Overlay
Green Channel of WSN - Soft Light or Overlay at 50% opacity
Ambient Occlusion - Multiply at 50%
Base Diffuse Color - Standard Blend

And then I have a layer at the top of the stack that I paint on to tighten up areas or get very specific shading.

Exroath

Wow .. I had no idea this was possible .. Especially to keep that amount of detail.
I love you guys

Dave Jr

Wow amazing ;D

JustColorado

I haven't tried that PRTP method yet. It looks good. But I have gotten very nice results doing an AO bake in xNormal, along with a Cavity map bake in XNormal. Then I take those 2 and Overlay them in potatoshop :-) onto the diffuse and playing with the opacity until it got me the look I wanted. To make it really pop, try overlaying the AO and cavity more than once. This was able to show a lot of detail without the normal map. In a lot of cases the normal map was not even necessary after that or had very little benefit.

Here is an example of a 10k tris model I am working on now, where I used 2 overlays of AO and Cavity. You can see that the normal map doesn't really add much. Just a little better detail for the face.

Sorry if this shot is a little intense, I haven't gotten around to making her outfit yet.

dongyfeng

Fingus wrote: »

Not sure exactly why I used both a WSN and pRTP with different blending modes. The way I usually do it now is roughly this:

Cavity/Curvature - Overlay
Green Channel of WSN - Soft Light or Overlay at 50% opacity
Ambient Occlusion - Multiply at 50%
Base Diffuse Color - Standard Blend

What is WSN? World Space Normal map?

A-N-P

Yep ^

dongyfeng

Thanks for the reply. I have a few more questions regarding highlights:

1. In @Joopson's post, the character has some highlights on pants and wounds. Is it hand painted?
2. In @Fingus's post, the green channel of the Bent Normal/PRTp looks very shinny, which is very cool. How it is made?