Next gen car - questions

LlamaRider

Yo everyone!
This is my first post so I want to say you hallo
I have some questions about next gen cars - like in GT5, NFS, DIRT etc. Do I need to make a Hi Poly model and after that model a low poly with normalmap from it? Yeah it's cool - new cool renders but... do I really have to? Yesterday I downloaded model of Pagani Zonda F from NFS Undercover to check how it's made and it doesn't have normal map, just diffuse textures.
http://speedy.sh/rqwDQ/Zonda-Test-2.rar
Here is "little game" made in Unity 3d and in my opinion this car looks just good.
So what I have to do? Start with low or hi poly?

cryrid

So what I have to do? Start with low or hi poly?

There are areas inbetween the two.

Here's a recentish thread on the issue: http://www.polycount.com/forum/showthread.php?t=94200&

mLichy

Well, it depends on the game. Something like Halo, we did normal maps for vehicles. But for games like Forza, they did higher poly meshes, and its just a flat color shader, with maybe some speckles tiling across it, and good reflection/fresnel.

LlamaRider

cryrid - thanks, I just couldn't find thread about it.
mLichy - maaaan thanks, now I know how to model. I must tell my friend that he was wrong

mLichy

No problem. He might be wrong in some regards, but not all games do the same.

GTA IV uses same methods as Forza, but I think Saints Row does both methods. I'd say anything more realistic, just do higher poly with shaders, except interior, ect. But for something like the warthog, do HP and bake down. As always, you don't have to follow this, but it's more often how things go. Just depends on the style.

Xoliul

Normalmaps really aren't an option when you want perfect reflections on your car body. Reflections are what it's all about, hence Mlichy's example of the warthog ( reflections aren't very important for that one). It's just not viable to try and attain perfect reflections with normalmaps since you'd need something like 16-bit 4k textures at least, which is impossible in UDK for example.
Doing a "mid-poly" model is less work (if you know how to model this sort of thing) and still looks better.

Ace-Angel

Plus, don't forget managing Reflection distortions akin to world masked bending is much easier on a Poly level vs. Normal Maps level.

LlamaRider

Yo guys again.
Today I have another problem.

The problem are these ugly black places. I know that I have to make more edges around the extruded region but is there something more to do?
Any idea how to solve it?

Xoliul

More geometry, simple as that. You can use smoothing groups as well, but in real cars you never have these razor-sharp edges like smoothing groups create.

mLichy

Yeah, you need to add in chamfers, and bevels, ect more geo like he said.

If you have a Box for example, and set it all to smoothing group 1, it has to try and normalize/wrap all the Normals around to an average, so you get darkening and artifacts. But sometimes this is done in a way, to help remove/fix normal map seams/issues.

http://matthewlichy.com/Personal_Belair_Coupe_57.html

Maybe my vehicle will give you some ideas. I'm not saying what I did is right/good, but it's what I did at the time. I'd prob. do some things different now, but I added more geo in places for proper deformation for GTA IV damage.

Xoliul

While Matthew's car is a good asset by itself, i wouldn't exactly call it a true "mid-poly" (stupid term but how else to put it) asset. You can still see sharp lines from smoothing groups on it.

The best example I can find right now is David Finlay's work:
http://3dfinlay.com/html/veh/mcla.html

to summarize a few key things about the method:

-Like high-poly modeling, you chamfer/buffer your sharp edges with more edges, to correct the shading
-Unlike highpoly modeling, you can use tri's and quads all the same, it doesn't matter as long as the shading is good.
-Unlike highpoly modeling, you can't rely on the subdivision algorithm to round things for you, so you need to model them as round/curved as you want them. This is what makes the modeling so difficult, as you have to keep things smooth on a very dense mesh. Proper workflow is essential!