I'm in the process to improve our lighting workflow at work.
No one here has really skills on advanced lighting technics.
Also I'm a simple cg artist and technical papers are beyond me.
I'm very sorry if my technical vocabulary is approximate and my post as messy as my brain.
We need to stay "mass appeal" (also web appeal
) so we can't use top full dynamic lighting with ssao and stuff. So i've looked at Radiosity Normal Mapping aka Directional Lightmaps technic from valve hl2, which looks to be a good compromise for us.
Basically it allows to use normal maps on totaly prelit models, with 3 lightmaps storing the lights incoming from 3 directions.
aka the normal map influences the diffuse of lightmapped models.
As described here
and improved here
with self shadowing normal maps
I've found many informations, mainly from researches of Ali Rahimi.
who generates the 3 lightmaps in Maya with Turtle there
Last version of lumonix shaderFX
includes a radiosity normal mapping node.
The shader needs a modified normap map called ssbump in order to speed calculations. ssbump can be generated with this
Then the normal can't be used anymore for specular calculations but it's another problem.
I was looking for a way to generates the lightmaps with Vray in Max. Our editor doesn't support lightmaps generation *shrug*
From what i understand, there's 2 way to achieve it :
Screwing mesh normals with a maxscript so they all point in the right direction before each lightmap generation.
Using a NormalBump/vraynormal in the bump channel of the max/vray material, special normal maps based on valve paper. I'm using maps from Viik on this thread
I quiet fail atm because light doesn't seem to come from the right directions on my normal map. Actually it's like there's no logic. On the same "angle plane", normal map will react differently :poly132: I bet it has to deal with uv and tangent/binormals stuff. I tryed with swapping RGB maps but no success. It's a bit complex to me.
I know Neox from polycount used directional lightmaps, generated with vray on Airborn
so i guess, it's possible
Do you use the same process to produce directional lightmaps in 3dsMax ? Can you describe it ? yeah Neox, you !
I don't understand which transformations i have to apply on my mesh normals to screw them the right way. Do someone has a little script to do it based on vectors desribed by valve's paper?
I read that UDK doesn't use this technic anymore. What coud be the alternative to use lightmaps and normal maps at the same time and at low calculation cost ?
Thank you very much for you time.
For the record : UDK uses the same technic for their 3 components lightmaps though it is coupled with a shadow map, to hide specular in shadowed areas.
Their "simple lightmap", used in the citadel demo, is just an HD basic lightmap with the normal maps relief baked into it, thus, theres no normal map in the final file (and no specular i guess)