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View Full Version : Vehicle: btr-70 APC with normal mapping


Staffan Norling
02-08-2004, 08:39 PM
2986 trangles.
Four texture maps: One 1024 normal map and one 1024 color map for the main body. One 512*128 normal map and one 512*128 color map for the wheels.
Pictures below where rendered with a single shadow-casting point light + ambient (a lighting setup as simple as it would have been in a game engine)

Modeled in Maya, normal maps generated with raydisplace (www.drone.org)

http://www.3dluvr.com/staffan/btr70lo6.jpg
http://www.3dluvr.com/staffan/btr70lo7.jpg

All comments are welcome.

kyldub
02-09-2004, 01:04 AM
nice model.


could you do something for me though? im curious how much the normal mapping helps on a model like this. mostly we see normal mapping on big organic monsters. so would you mind rendering it without the normal map so i could see the difference?

ShortFuseNZ
02-09-2004, 01:36 AM
Nice model lookin good. Nice poly count too.

Im interested too. So far ive only seen normal maps used on Organic models like humans or game characters. Also could you post the normal map so we can have a look see :)

Neil
02-09-2004, 01:41 AM
That's exactly what i was thinking too... and i'm looking at this and i can only see a few parts where i think it's being 'bumped' and in which case they're still not very important to the overall piece. I dunno, i'm still not a big fan of normal mapping, maybe i'm biased ;)

Gibbz
02-09-2004, 05:47 AM
yeah i too think the normal maping looks like its just been textured on... tho in game with dynamic lights it owuld be diffrent. Like doom has normal maped walls but i think some ut2k3 levels look more real than dooms normalmaped walls, tho normal maping is great for characters because they move! :)

Staffan Norling
02-09-2004, 09:34 AM
With color and normal mapping: http://www.3dluvr.com/staffan/btr70lo8.jpg

Without normal mapping: http://www.3dluvr.com/staffan/btr70lo9.jpg

With normal mapping but without color mapping: http://www.3dluvr.com/staffan/btr70lo10.jpg

Without nay mapping: http://www.3dluvr.com/staffan/btr70lo11.jpg

As you may see, the normal mapping dos'nt do any huge work improoving the model...but it certainly looks better. In commercial game production, i doubt would it be worth the money to pay off high polygon modelers to do this...Creating normal maps by bumpmapping would probably create similar result in less time (allthough you would have to be without stuff such as chamfered edges and perfectly roud surfaces then).

mv
02-09-2004, 01:22 PM
I think it looks great, and that normal mapping adds a lot. Esp on the tires! great job there. I'd like to see a quick anim to see some dynamic lighting and specular action, that's were normal mapping shows all its usefulness.

Matt
02-09-2004, 01:28 PM
The normal mapping is killer on this. I'm really surprised with the quality look of the wheels with the normal maps applied. Great job.

Did you do something to blur some of the edges? Some of the edges look like the normal maps are blurring them and making them higher poly in appearance.

Staffan Norling
02-09-2004, 02:43 PM
Originally posted by Matt
The normal mapping is killer on this. I'm really surprised with the quality look of the wheels with the normal maps applied. Great job.

Did you do something to blur some of the edges? Some of the edges look like the normal maps are blurring them and making them higher poly in appearance.

I beveled the edges of the high poly model...

LoTekK
02-09-2004, 02:51 PM
Great looking model, and the normal mapping definitely ads to the look.

If I may add my 2 cents to the comments about mechanical objects not benefiting as much from normal mapping:
If you think about it, mechanical objects, in a sense, actually can benefit more from normal mapping than organic objects, since the predominance of straight lines means silhouette is not nearly as much of an issue as with organic objects. As for the prevalence of normal mapping for mechanical stuff, it's definitely out there, but the "wow" factor right now is for organic stuff. I seem to recall CryTek's polybump previewer had a power generator as its first sample model to show off the normal mapping in Far Cry's graphics engine. Silent Storm (turn based tactical game along the lines of X-Com) makes heavy use of normal mapping in both the organic and mechanical models.

Staffan Norling
02-09-2004, 06:37 PM
Originally posted by LoTekK
Great looking model, and the normal mapping definitely ads to the look.

If I may add my 2 cents to the comments about mechanical objects not benefiting as much from normal mapping:
If you think about it, mechanical objects, in a sense, actually can benefit more from normal mapping than organic objects, since the predominance of straight lines means silhouette is not nearly as much of an issue as with organic objects. As for the prevalence of normal mapping for mechanical stuff, it's definitely out there, but the "wow" factor right now is for organic stuff. I seem to recall CryTek's polybump previewer had a power generator as its first sample model to show off the normal mapping in Far Cry's graphics engine. Silent Storm (turn based tactical game along the lines of X-Com) makes heavy use of normal mapping in both the organic and mechanical models.

Normal mapping does'nt only make things look better, it could also be used to replace geometric detail with textured detail. The polygon count of the characters of Battlefield:vientnamn, for instance, is lower than the polygon count of the characters of Battlefield:1942. This is due to the use of normal mapping in the new game...

And reducing the polygon count of characters is something that you really would like to do in any game, since the vertex density is generally high and skeletons and deformers increases the render time pretty much.

So...even though vehicles and static geometry could benefit from normal mapping, there is a lot more optimizing that could be done for characters. Using normal maps for vehicles and static geometry may slow down the game....but using it with deformable objects may on the other hand speed it up.

LoTekK
02-09-2004, 06:43 PM
Originally posted by Staffan Norling
Using normal maps for vehicles and static geometry may slow down the game....but using it with deformable objects may on the other hand speed it up. [/B]
Hmm, I never really looked at it that way. Good point. But normal mapping on mechanical objects still means the difference between a three hundred poly weapon and a three thousand poly one. And texture mapping doesn't really cut it when dynamic lighting and shadows are becoming more and more prevalent in game engines.

Howard Day
02-09-2004, 09:22 PM
Howdy, Staffan! I haven't seen you about for a while. :D Gotta say, that normal mapping stuff has got to be some of the coolest tech I've ever seen. The only thing I'd say is that you might want to check out...wait.. you've already seen the drone.org tank example. Never mind. :D Not to hijiack the thread, but them normal maps make good space ships too....
http://www.qspeed.com/eridani/models/2.8.04/
I think that entire thing is around 1500 polys.
Hope you like it.

Howie

Staffan Norling
02-09-2004, 09:40 PM
mmm...spaceships...

Creating spaceships with normal mapping for space combat simulation games gotta be one of the most enyoyable professions there is...Unfortunately, the normal mapper that i've used works best when the highpoly model is a single surface. All people that knows how my spaceships use to end up would also understand the enormous pain that booleaning thoose greebles together to a single surface would cause...:D

Howard Day
02-09-2004, 10:28 PM
Amen.
Fortunately, the system that my game uses only requires a mesh - not connectivity needed. :D Plus - The way I do it does not require a hi-res mesh to generate the final normal map. Instead, I un-wrap the mesh and then use the map coordinates as a template and build geometry up on to of that flat plane. The end result is the same - but you don't need to spend the time to make a freaking-high-resolution model. this approch should be platform independant. you might want to give it a shot :D

Poopinmymouth
02-09-2004, 10:32 PM
critique: I have both images up, with and without, and can barely tell the difference. It looks as if you used it to create a few raised spots, and a couple lines. I would like to see the hi poly and low poly versions next to each other with just the flat faces and wireframe showing.

Haveing made alot of high poly objects for normal mapping, you can achieve much more extreme results.

So as not to make this an entirely negative post. I do really like the wheels, and the headlights.

fattkid
02-10-2004, 01:47 AM
Hey Staffan, the model looks quite nice, the normal mapping seems to give the vehicle a bit more volume and shape, but the effect seems pretty subtle, which is understandable given the design of the vehicle. I've got a couple quick newbie questions that hopefully you (or someone) can answer..........once you make your normal map, how do you render it out in Maya? (I'm using Maya 4.5 and the ATI plug in). Where do you plug the normal map into the material attributes for the low poly model? Anything in particular you need to do with the lights or anything? Or any other pointers? Thanks for any answers, and good job!

Staffan Norling
02-10-2004, 09:26 AM
I am using raydisplace to generate normal maps. It uses raytracing to sample the normals of the high polygon objecct.

Basicly, you set the high polygon object to only be visible in reflections. The low polygon object should only have primary visibility.

Then, you assign a simple shading network to the low polygon object (a ray displace node, a set range node that converts normals to colors, and a surface shader)

Then you bake the low polygon object (render it in uv-space, that is). For every pixel in the rendered map, Raydisplace casts a ray from the low polygon object, the ray hits the high polygon object and samples the normal. The set range node converts it from "-1 to 1" range to "0 to 1" range, and the color is then saved into a normal map.


To use the normal map in a game, it would probably have to be converted from object space to tangent space...this is a little bit tricky, but there is a nice workaround for this at www.drone.org.

To render the normal map in maya, object space works fine. All you have to do is input the normal map as a file texture, get the out color from it, input it in a set range node that converts colors to normals (from "0 to 1" range to "-1 to 1" range), input that into a node that converts the normals from world space to camera space (this could be done with the space change utility that can be downloaded from www.drone.org or www.highend3d.com , or you could use maya's vector product node to multiply the normals with the cameras world matrix. This conversion does'nt have to be done when using Mental Ray, since it seams to use normals in world space(!?!)). Then just stick the converted normals into the normal camera input of the material that you want normal mapped.

It's all like using bumpmaps, allthough you use other nodes than the bump2d node to convert your file texture to normals of an object.

There are tutorials and example scenes at www.drone.org ...if you have a little experience in creating shading networks, you should be able to analyze the example scenes and create networks with the same functionality yourself.

fattkid
02-10-2004, 09:41 AM
Awesome! Thanks for the lowdown. This stuff might be a little beyond me but I'm gonna see what happens. Very much appreciated!

Staffan Norling
02-11-2004, 08:50 AM
Here are two shots of the high polygon model...unfortunately, i dont have any renderings made with the same lighting and angle as the lo-polygon shots.


http://www.3dluvr.com/staffan/btr70hi4.jpg
http://www.3dluvr.com/staffan/btr70hi5.jpg

fattkid
02-11-2004, 09:41 AM
Hey Staffan, I think I got the normal map to work but I was hoping you could take a gander at the image on the link below and tell me if everything looks right. It's the shading network, with the attribute editors open, and a test model. I downloaded one of the scenes from www.drone.org to grab the shading nodes and hooked them up as you said. Hopefully you'll have a moment to reply, and thank you for your help.

http://www.trevorsart.com/NormalMap.jpg

Staffan Norling
02-11-2004, 03:09 PM
all setting seams ok...and it seams to work just fine. But if you want to move your object around, you should set the in space to object instead of world (...it will only work if the object where aligned with the world when you did the normal map) .

costas
02-12-2004, 11:24 AM
no comment

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