07-06-2004, 02:23 AM
I heard about "normal maps":
A model is modeled high poly with milions of polys. Then the Polys are reduced to a few thousand. A normal map is made out of the high poly object and applyed to the low poly object. Then the low poly object has as much detail as the high poly object but renders a lot faster! (Used for doom 3 for example)
How does that work? can i do that with max as well?
07-06-2004, 08:47 PM
I don't know if you can do it in max 6, I have only done it in XSI.
But the tech behind it is all shaders, I don't know if you are expert with shaders, but basically it is like bump mapping, but it is called poly bump, so the shader library is written from the high poly model and traslated to the lowpoly model, so the shaders work with the lowpoly model like they'd do with the high poly.
Because high or low poly model, it is all about light. And shaders make it look like really detailed model. You should look the HL2 video where they explain the use of shaders, I think you can find it in fileplanet.
08-06-2004, 01:57 AM
I see. Yes I now what polybump is. Thanks for your help!
11-06-2004, 06:36 AM
which HL2 movie you mean??I cheacked and there 's like 5 or 6 movies there..
p.s. you mean by HL half life don't you??:D
11-06-2004, 12:39 PM
Hello there... Mr Freeman Sorry... to have... awakened you...
very good hl2 preview you get to see playtesting and stuff
11-06-2004, 12:41 PM
Rise and shine Mr Freeman... Rise... and Shine..
very good hl2 preview you get to see playtesting and stuff
14-06-2004, 10:42 PM
normal mapping is the technique with which.....a low polygon reflects the light of a high polygon model...pretty ingenious technique...th elow-polygon model uses a map which provides it with light values.....
here are a few(i dont think few) links i found....i dont think u wud need anything else after this...;)
Nvidia has a Photoshop filter plugin to convert a grayscale bitmap to a normal map. Works OK, but geometry gives much better results, which it doesn't handle. The plugin has a helpful previewer, and many options. The normal map converter is also bundled in with their DDS exporter, if you wish to go that route.
ATI also has a 2D bump map generator, to convert images into normal maps, similar to the Nvidia tool.
ATIís normal mapper generates normal maps from geometry and bump maps, works OK, is free, and is also open source. Comes with a handy previewer too. Lots of options. Comes with max3, max4, and max5 exporters to get your geometry into the tool. Now has a GUI too.
Mike Bunnellís modification of ATIís tool that uses OBJ files instead of ATIís NMF format. Optionally creates a sub-division surface for you. Creates displacement maps. Supports 16-bit TIFF. Etc.
ORB is another normal map generator, converts 3D models into normal maps. Also generates displacement maps, diffuse maps, vertex-color maps. Imports ASE/OBJ/LWO formats. Previewer included.
Discreet's utility plugin Normal Render works OK, but requires a similar UV layout between the low-res and high-res objects. This can be quite limiting. Not many options in the tool. Works with max4 and max5. Free registration is required to download the file.
Ben Lipmanís gNormal plugin goes in the bump channel of a material, allowing you to use your normal map in the 3ds max renderer.
Ben Lipman mentioned on the Discreet forum that John Burnett's NormalTexture plugin can be used with max5ís Render To Texture to make normal maps. Not sure how this works, havenít tried it.
Texporter can create a normal map from high-res geometry, as long as the UVs are there. Although I should point out it is a world-space normal map, thus you shouldnít rotate or deform the final model that has the normal map on it, because the shading will be horrible. World space normals are best for static objects in your game.
Nvidia has a tool they're about to release called Melody. It can create the low-res model automatically (seems pretty good, as far as auto-LOD is concerned, but of course never as good as manual) and they wrap the whole thing in a GUI.
Some opinions here:
Peter Watjeís Object Texture plugin generates a normal map from geometry and places it in a material, so you can render it with the max renderer. However, the map is tied to actual geometry in the scene, or cached in the material, but it cannot be exported into a bitmap. I just thought Iíd provide a link anyhow, since it comes with full source code.
Polybump generates normal maps from geometry, optionally including height-map bump maps. Includes 3ds max and Maya plugins. Includes code for integrating the effect into your real-time 3D engine. Includes standalone viewer.
Mankua's Kaldera is the best so far in my opinion. Not just because I helped them develop and test it, but because it is so flexible and works right in max. Lots of control over how the normals are generated. Bakes several channels at onceÖ diffuse, lit, lighting only, normals, height, alpha, etc. Bakes multiple objects into one, including atmospherics. Comes with a handy normal map texture plugin, for using normal maps in the bump channel with the scanline renderer (also works in Brazil a friend tells me).
HOW TO VIEW NORMAL MAPS
Using the default viewport shader:
1. You need a graphics card that supports pixel shaders in DirectX.
2. Set the viewport to use Direct3D.
3. Set the Viewport Manager rollout of your material to use Metal Bump, and enable it.
4. Load your normal map in the Normal slot.
5. Set the viewport to Smooth.
6. The Metal Bump shader doesn't work on poly objects, must be mesh. Collapse to Editable Mesh or else add a Turn To Mesh modifier on top of the modifier stack.
7. I found the MetalBump shader also displays the normal map as the color map, at the same time. To stop this, I place a white bitmap in the Texture1 slot.
8. Canít remember but I think this process also works in max 4.
Using a Cg viewport shader:
Ben Cloward explains how, and provides a sample shader...
In the 3ds max 5 scanline renderer:
1. Gnormal is a freeware texture plugin. Put it in your Bump channel and load your map.
2. Kaldera is a commercial package that includes a texture plugin. Same process.
Steve Green mentioned on the Discreet forum that Mankua's plugin provided slightly sharper results than Ben Lipman's, when he compared them using with the same material settings. Ben may have modified his plugin based on this, not sure.
ATI VS. NVIDIA
ATI and NVIDIA each use different normal map formats with their graphics chips.
Basically ATI expects the green channel to point the normal upwards, while NVIDIA expects it to point downwards.
The MetalBump shader in 3ds max uses the NVIDIA method.
Mankuaís Kaldera has the option to output either ATI or NVIDIA format. Iím not sure about the other tools.
One sure-fire method to fix a map thatís incompatible with your viewer is to simply invert the green channel in your image editor of choice. By inverting I mean the black pixels should be white, and the white pixels should be black.
TIPS AND TRICKS
Ben Cloward posted a strong full-featured normal mapping tutorial on his site. It also has a lot of software-agnostic information.
Gary Pate (a.k.a. Ionized) has a great tutorial using 3ds max and ATI's normal mapper.
James Hastings-Trew describes normal maps in plain language, with tips on creating them in Cinema 4D.
Polycount thread containing tips about painting/editing normal maps.
Polycount thread explaining World Space vs. Object Space vs. Tangent Space.
Polycount thread dissecting Doom IIIís use of normal mapping.
Digital Sculpting Forum threads about normal mapping/displacement extraction.
Should be enough to get you started...
Are there any maya tutorials?.
It seems everyone around here only uses max. Sucks for me 'cause I use Maya
14-09-2004, 09:51 PM
I think I saw this supported natively in Max 7. Which should be out in a few weeks.
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