Normal map wiki page

Eric Chadwick

OK, been slowly condensing and updating and re-writing things.
http://wiki.polycount.net/Normal_Map

I wonder if anyone has some art samples they could contribute. Too much text!

I'm looking for some art that shows mirrored UVs, but with the mirror seam offset from the center. Like Ben's faces here.
http://www.benregimbal.com/Step_face_I.jpg
But it'd be great to show something on a mesh, so the kids can see how it's done. :poly128: Like, here's the seam, and see how artfully it's painted to hide said seam.

Michael Knubben

I don't have any examples to share, but I just wanted to tell you how much I appreciate the work you've put into the wiki. It's all very clearly explained, and yet doesn't hold back any information. Just wanted to share my appreciation.

Rick Stirling

It's great stuff Eric!

One thing that might be worth adding to the RGB channels part is that if you do swap colours around like your compression example then it looks like the normal map has changes - the blue/purple tangent space map becomes green to the observer.

By the way, I don't know the correct term, but we use this technique and call it Swizzling. We end up with Swizzled normal maps. It might be the correct term, but them again I wrote a script that re-orders the bones in the max skin modifier and it's called Skelatordorator.

kio

yay thats really good stuff you put there together.

Eric Chadwick

You're welcome. If you guys think of anything else that could be in there, give me a shout.

Thanks Rick, will work that in somewhere. I've heard swizzle before, just looked it up the other day, wikipedia said it's a math re-organization term, very similar to the color channel swap.

CrazyButcher

you should link towards that id software article on normalmap compression (would myself waiting for account ) as it's really abundant

http://developer.nvidia.com/object/real-time-normal-map-dxt-compression.html

Eric Chadwick

Added, thanks CB.

Eric Chadwick

I whipped up a quick example of using an inverted normalmap to fake subsurface scattering on the undersides of sunlit leaves.
http://wiki.polycount.net/Normal_Map#Renormalizing


Needs some finesse, but it's cool when something just works, ya know?

Does the explanation I wrote make sense? Maybe I need more pictures.

TWilson

Hey nice job on the wiki! That's fantastic.

I wish this stuff existed when I was picking up next gen. I'm glad it does now at least. Super neat leaf trick.

killingpeople

EricChadwick, you're awesome for pulling all this info together so well in the wiki dude. kudos.

IronHawk

Eric thanks for all the hard work on the Wiki!

Eric Chadwick

Thanks kp. If there's anything missing, I'd like to add it.

It's also mirrored now on the tech-artists.org wiki.

16bit

Why is the Smoothing Groups & Hard Edges section lined out? It looks correct to me, shouldn't you use smoothing groups? I just re-baked my normal map for my gun with only one smoothing group and the normals were completely destroyed.

EarthQuake

I think that section is simply being re-writen

Eric Chadwick

I need to re-write it. Basically, the best results tend to come from using hard edges wherever you have UV seams. But your baking app has to use a cage mesh to cast from, instead of pure distance, otherwise you'll get gaps.

rumblesushi

Excellent job Eric, there's some great info there. I'll have a proper gander through the whole polycount wiki to get up to speed on modelling techniques.

Eric Chadwick

OK, re-written.
http://wiki.polycount.net/Normal_Map#

Feeling a bit of writer's fatigue though. How does it read?

claydough

EricChadwick wrote: »

OK, re-written.
http://wiki.polycount.net/Normal_Map#

Feeling a bit of writer's fatigue though. How does it read?

It would be really nice if there was a wiki link on the front page.
Or better yet...
A supporting wiki thread at the top of the front page with links to Wiki pages.
I keep forgetting to take advantage of this great resource.

Thanks for all the hard work Eric!

Mio

awesome update ,thanks alot~

Electro

Nice work Eric!

Yes, the term is called swizzling (to switch things around )
One nitpick, the "bitangent" you speak of, is referred to as the binormal.

Again, excellent work and it's good seeing everything all laid out in a "1 stop" go to for normalmapping.

Eric Chadwick

Thanks guys, glad it helps!

RE: binormal, this guy seemed to think it's a misnomer.
http://www.terathon.com/code/tangent.html