Cars, keeping a clean mesh?
polycounter lvl 11
Recently bought GTAIV for the PC (ive had it for the xbox) and have become sort of motivated to model some cars, but my first few attempts failed because of little mesh errors in shading because of my topology and little bumps in the mesh.
I downloaded some mod tools to view the models of some of gta's cars to see some topology, and its amazing how neat it looks. It almost is like these cars are generated.
Heres a picture of a comet:
Youll notice how smooth it is, but the more polygons i add to my mesh, the more bumpy it can get. I was thinking that its possible that they model their cars low poly and then turbosmooth once, but that doesnt seem right because their cars don't use normal maps, and theyre about 13k polys.
Could anyone help me out if you have experience with this? All tutorials i see for cars are usually high poly.
I downloaded some mod tools to view the models of some of gta's cars to see some topology, and its amazing how neat it looks. It almost is like these cars are generated.
Heres a picture of a comet:
Youll notice how smooth it is, but the more polygons i add to my mesh, the more bumpy it can get. I was thinking that its possible that they model their cars low poly and then turbosmooth once, but that doesnt seem right because their cars don't use normal maps, and theyre about 13k polys.
Could anyone help me out if you have experience with this? All tutorials i see for cars are usually high poly.
Replies
mesh smooth isn't limited to being used with normalmaps.
http://www.game-artist.net/forums/work-progress/10894-2009-bmw-x6-m-series.html
also cg-cars.com is a really good place for car modeling help.
As far as just keeping a mesh clean goes its mostly just being really careful with your verts. Some times if I have a really messy loop I will delete it start over on getting the verts into place.
No. If you turn on "separate by smooth group" in the turbo smooth modifier it only smooths across the same smooth group. You make hard edges by applying different smoothing groups. Because of this it doesn't bunch the polygons together to create these hard edges.
here's a quick example I made showing what I mean
smoothgroups_meshsmooth by sprunghunt, on Flickr
Thanks man, will try again!
Like this:
So normal sub D modeling techniques should be a better bet.
Or just not use polygons to start. Use patches instead, and convert to polys.
I'm not confortable with SubD for modelling this, and would like to see any other technique
I wonder, as IV cars have 3 LOD models, if these were used for modelling. The first lod level, that appears after a few meters, could be the 'base' for subD or any other tesselation technique. I haven't checked the LOD levels so don't know if this sound stupid.
Also, take in mind, for IV, as the damage is done displacing vertexes, the topology has to be consistent :P
Also, couldnt you use sprungs method but manual smoothing by chamfering hard creases?
But i think my take would be model it in "normal" subd's with control edges, and then collapse the modifier stack(freeze the mesh) and then start optimizing the mesh by deleting edge loops.
I would probably do as others suggested and combine meshsmooth with some strategic chamfering after the fact.
Something to note is that you don't have to use the meshsmooth modifier. You can smooth faces at the polygon level using the "mSmooth" button under the "edit Geometry" rollout in edit poly.
Wow, I didn't know that was possible. I've just been adding lots of supporting loops resulting in scruffy bits in places. Ta :thumbup:
Can someone also explain patches, im guessing it has to do with modeling with splines, and is that a good way to model cars?
Yes - I'd use the face smooth function if I was making something and I wanted part of it to be rounder. For example if I was making a chair and wanted to add a cushion.
By patches they probably mean using bezier patches or nurbs. It's not better than polygons in my opinion. But that depends on what you're used to. Nurbs can be a huge pain.
Either way you'll still end up having to polygon edit your final mesh as patches rarely produce an optimised result.
I generally make the shell of the car with turbosmooth, just like a regular highpoly mesh, getting the form as close as possible to the refs but ignoring any non-formbearing cuts and holes (any seams- doors etc, wells for lights, grill hole and etc). Then i collapse it to poly and optimise the crap out of it, manually removing edgeloops that aren't contributing to the silhouette or are unecessary for whatever reason. Once that's done, all the holes that were ignored can be manually cut into the mesh. If the mesh was the right shape to begin with they sit perfectly where they need to go, but odds are they'll need tweaking. I generally ignore the established topology at this point as it's not important anymore, but always be wary of making poles. The rest is finished off with traditional techniques.
The key is basically using turbosmooth to make that nice smooth and sexy look, and trying not to alter the shape after that.
Ive split up the entire carshell into pieces (door, hood, etc). But.... how do i get the nice beveled edge between the pieces like in real life?
I didn't make a porche, i actually made a MB SL but heres what i mean(lines where the door opens etc):
Sorta found a solution. I had to reweld all the pieces of the car so it was solid again, select the seams and chamfer and then extrude inward a tiny bit.