NORMAL MAPPING in XSI?

[ASW]

GPU SurfaceFX, the third one down, I havent tried it yet, anybody who has, give us a shout out, I'd like too hear how it works. Hope that points you in the right direction. Hey If you know how to merge multiple texture definitions into one uv unwrap let me know. word

[Atyss]

Go to XSI Base and make searches for Normal Mapping in the How I Did It and Rendering sections. There are a couple of very detailed threads about that. Also, if you can get your hands on Highend Magazine #3, there is a long -and great- normal mapping tutorial for XSI.

I should add that normal mapping has not be "implemented" in XSI. In XSI, you do normal mapping with the standard render tree nodes provided with the software.


Cheers
Bernard

[dbach]

Also if you check the new feature vids for XSI 3.5 on softimages website there is a vid on normal maping.

- Don

[ThE_JacO]

let's start from the basics...
there's 2 kind of normals in any geometry, one is explicit normals, or geometry normals, and those happen at every vertex of your item.
the other kind is interpolated normals and those happen everywhere else :)

normals, in 3D space, are the very first thing defining how ur object reacts to light, and how ur object reacts to light is 80% of what makes it look real.

if you take normal rendering processes (and we can mean both MRay or openGL being the rendering engine here) and pipe the normals thru a phong illumination model you only really have your geometry normals in the scene, but the algorithm defined by Mr Phong eons ago determines how the interpolated normals should bend between vertices, and you get the illusion of a smoother shading.

take this a step further and go bump mapping.
all bump mapping really does is a "perturbation" process of existing normals according to a map.
it doesn't really elevate or depress anything according to that map, that is something only displacment can do, what it does i bending normals so that you get the impression of a different lighthing, and therefore different depth.

bump mapping tho has a limit, and it's that of only being able to perturbate vectors on a range of 180 degrees and only working with a luminance channels, while for massive asswhopping process we need to define precise vectors on a 360 degrees range.

normals are simply vectors, and vectors are described by intensity along X, Y and Z.

so, if we pair X to red, Y to green and Z to blue, and figure out some clever way to tell it when it's negative and when it's positive, we can descrive any vector we wish on the surface.

what normal mapping does is analyzing ur model, and for each surface normal creates a pixel in a texture with RGB values corresponding to what normal orientation that point on the surface had.
if we then use that map (that came from the high res model) to alter the normals on the low res one.. bam! u get normal mapping, basically a clever all around bumping with great precision.

now how do you get this in XSI ?

first you need to define such maps onto the LOW-RES mesh.
This is done by piping vector info into the highres surface and rendermapping with camera distance that geometry onto the low res mesh.
if this sounds too hard don't worry, in the add-ons page in the netview there's a page called GPU-FX that has some setup scripts doing all this for you.

once you have these normal maps u need to visualize them, and so all you need to do is use a realtime-shaders network (add-ons offer helpers for this as well) to display them in the viewports.

saying XSI doesn't support normal maps natively is 100% wrong.
XSI does, since only an app with a realtime shaders support can show them that's what support is all about.

how they are generated is another matter, and in that it does a damn brilant job, because doing it all by rendertree with helpers it gives you automated processes to do it and yet you can fine control at any time in the pipeline.
actually how would one generate such maps if not by using rendermaps and rendertree nodes ? you can either show the engine or not, but all the app allowing this kind of mapping, either natively or by plugin, do it by some sort of rendermapping.

support or not is simply about visualization, and at that XSI does an excellent job.

[dbach]

Maby you guys can clear up a question of mine, can normal mapping be done when a geometry is textured using standard image mapping techniques (not using realtime shaders?) oh nevermind I finally understand Jaco's post :p

Edit: oh and KWAK from that view you look a bit like Nigel.

Thanx,

- Don

3d36

[ASW]

Kwak, did you go to the VFS 3d program? Also, Yes Normal mapping is just like any other form of mapping, bump, spec, transperancy. etc and can be used in conjunction with a Color map. At least thats what I understand.

[ThE_JacO]

u got that right, normal mapping happens like any other kind of mapping and follows the same rules (pixels placed by samples, samples organized by UV coordinates etc.).
color maps determine what colors ends up where, other maps, like specular, take care of how the point reacts to light, normal mapping just takes care of orienting the normal at the sampled point.

[seb4d]

Very interesting Topic !

Ok I used the little GPU SurfaceFX script and it seems to work.

But I don't want a real time shader, what I want is simply use my normal maps in a normal rendering process.
Where do I have to plug the normal maps in the render tree ?

ThE_JacO do you know how to do that ?

[ThE_JacO]

the simpliest way to use normal mapping in MRay is to use Bartek's shaders.

you can find the D3 suite (and some other really useful ones like diffraction and dirtmap) here >> http://www.xsibase.com/tools/shaders.php

you can do it by rendertree alone, but it takes way too many nodes compared to a nice packaged free shader :)

[seb4d]

Great !
I didn't notice this shader on xsibase before.

Thanks !

[KolbyJukes]

Hey everybody, wow so many responses. Thanks so much!

ASW: I'm in term 4 of the VFS3d program right now. so like, 5 months more and I'm done. woo hoo!

dbach: It's funny you should mention Nigel...for awhile I had one of those lip piercings like he does, and everybody was calling me mini-Nigel.

Thanks again for all the great responses everybody. Very much appreciated.

-Kol.

[seb4d]

And here is the official d3 normal mapping tutorial :
http://be3d.republika.pl/howto_d3_normalmap.html

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