Home Technical Talk

Car modeling techniques

Hi I am after some advice on car modeling techniques, more specifically for games
in most games now damage is a big part of game play and thus how the car is modeled, this must mean that all the panels are now separate instead of backed or textured panel gaps.

as games require a limited polygon count how would one model this, would you model all the car as a single mesh, getting edge flow following everything through the entire car or model each part separately allowing different edge flows from piece to piece.

for example the lights on a car are not attached to the metal body, there may be a lot of complex geometry leading into the lights area, the lights wouldn't necessarily need all those edge loops to continue through them, so in industry would they model it separately disregarding the surrounding geometry or would the car be modeled as one and then detached at the end to its separate parts to ensure perfect match up of shape? (there could be minute differences in shape with different amounts of geometry on adjacent panels. also I would image that it would be entirely possible than mesh smooth may also change some shapes right?)

Edit*
I remembered this image from some time ago, this is one of the best "potential real time" car model I have seen,
Koenigsegg_28_3840.jpg

they have theirs continuing over some parts, however the front bumper is different and the thing that most stood out to me was that it has tri's, now this inst anything bad, however for meshsmooth I was always taught to have 100% quads, if the car in this image was not intended for meshsmooth then there is a lot of optimisation to be done, especially at the top of the front wheel arch, the polygon distribution seems a little off, having too much in one area than another.

Replies

  • Drav
    Offline / Send Message
    Drav polycounter lvl 9
    This car has been made as a one piece smoothed shell to get a smooth shape, had the smoothed shape collapsed to a mesh, then had the bodyworks lines cut into it, hence the tris.

    Loads of different ways of doing things, Im no expert, but I prefer subDing a shell, with most of the lines in Sub D, then collapsing and deleting loops to optimise. I like to stay in quads for as long as possible, so do most of the lines in subd when i can. When it is a massive pain, Ill collapse the turbosmooth and do the weird lines after.

    Headlights I sort of make up as I go, but I generally dont have them connected to the main body.
  • ZacD
    Offline / Send Message
    ZacD polycounter
    It really just depends on the game, the engine, and what limits you are working with.
    http://speedhunters.com/archive/2011/11/17/behind-the-scenes-creating-cars-need-for-speed-run.aspx

    You are almost always going to have to use tris, cars are definitely not designed with polygons in mind, and you are most likely not going to be using normal maps, so you'll need a lot of tris in some areas just so it shades well.
  • Computron
    Offline / Send Message
    Computron polycounter lvl 7
    what I wonder regarding their method of mid-poly modeling is, do they interpolate the normals across vertices the same way as in the 3ds max viewport? I tried making one of the furlings with the same topology in the picture and it shaded strangely.
  • SkyWay
    Offline / Send Message
    SkyWay polycounter lvl 11
    ScottJ : I'd say a healthy "remember the rules. but learn when to break them" is appropriate concerning the tris. I'm modelling a Lambo Aventador at the moment and no way in hell am I gonna go full quad on it, just so I won't go mad. Quads help the subdivision process and making edgeloops is easier when everything's quadified, but I always remember that deep down under all the jazz 3D modelling software does it's all still made of triangles, even those quads.

    Computron: Max, as far as I've used it, is notorious for shading everything like crap even when your flow is smooth. They even made a hotfix for 2012 in order to "mend" their wonky normals... Preview with xoliul or 3pointshader and you should get a proper result. Also, Maya shades things a lot better for what I remember.

    Edit: Clicked the link after I commented and whaddayaknow, they talk about the Aventador :D
  • ScottJ
    thanks for the info, I agree skyway, I normally always work with tries and never worry about quads, most the time they are quads as that's how modeling goes, however never afraid to go to tri's,I haven't often made models intended for meshsmooth, the last time I did it was advised that the model I was working on had too many tri's for meshsmooth to be effective.

    It makes a lot of sens that they baked a meshsmooth and then played around to get tri's and a bit of optimization, something I hadn't thought about because the intended purpose of this exercise I have undertaken was to see how UDK's tessellation worked with something like this, along with Lod's and the normal method of stuff like this.

    as such I have tried extremely hard to keep it all quads in the hope that tessellation will work nicer with the model, while I have had a fair bit of experience with UDK, tessellation and the new features over the last year I have not had much time to explore and test.

    the overall shape of the car didnt take too long to do, but details like the lights and some of the trims are now trippeling the time its taken to make it due to this quad problem, as such I have made a saved version and gone into tri's to attempt to see how tessellation and meshsmooth will work though I already have a small pinching effect with the mesh smooth.
  • SkyWay
    Offline / Send Message
    SkyWay polycounter lvl 11
    Experimentation is always good :)
  • HAWK12HT
  • HAWK12HT
    Offline / Send Message
    HAWK12HT polycounter lvl 9
    I hope above posted image helps you. The image you have shown is almost 3 years old work intended for pre rendered animation, not for a game environment as far as i know when i saw it on CGS.
    As som1 already had posted Speehunters link :D notice that they mention "lot of vertix tweaking" to me that is the actual pain when it comes to low poly car modelling which btw im in my first attempt. Reason being that u can move 1 vertext to a certain height after that u can see 2 faces clearly on one poly, when u apply smooth group on that surface it bound to get ugly as it is exceeding its angle.

    notice black artifacting on middle top left of hood, this is solved by adding more polys,tris to such sharp angles :D. I have just used 1 SG and chamfering, to get as close as EA :D.
  • ScottJ
    you shouldnt be getting close to EA, you should be getting as close to the actual car itself, I notice alot of cars in GT5, Forza 3/4 that are not accurate and look nasty, they will do but you shoudl always be pushing more accuracy and detail than in current gen games.

    you have a good start there but without more subdevisions then you are not going to get the rest of the detail on the hood.

    evo81.jpg
    evo82.jpg
    evo83.jpg
    evoUDK.jpg
  • Computron
    Offline / Send Message
    Computron polycounter lvl 7
    88k tris for just the main body of a car? You can cut that down to sure with some custom vertex normal.
  • ScottJ
    thats mesh smooth :P, at level 2 at that, 5k without, shouldnt be an issue with the way I was planning on implementing tesselation., get it to decrease as you get further away
  • Ark
    Offline / Send Message
    Ark polycounter lvl 11
    You have plenty of edge loops in there that add no definition at all. Try to keep the quads evenly spaced and just use the other edges as creasing edges so you can add a level of turbosmooth, then you can remove the unneeded crease edges and work on the smoothing.
  • darthwilson
    In terms of damage think of what can physically come off, likes like the bumper etc. Since your plonking this into UDK you can easily use Animtrees to construct a damage system which uses static meshes and morph targets.

    http://udn.epicgames.com/Three/SettingUpVehicles.html
  • HAWK12HT
    Offline / Send Message
    HAWK12HT polycounter lvl 9
    I think check CGCars or SMCars.net. As for me getting close to EA is in terms of maximum details within 30k with all interior exterior wheels etc :D, thats why im keeping it way to low in polys and only chamfering or adding loops on KEY signature elements of the car :D. oh btw GAME ON :P
    (i ll let u win this time, im busy with other stuff lol)
  • littleclaude
    Offline / Send Message
    littleclaude ngon master
    Apologies for bringing this thread back to life but I would like to know more about the best practice for cars for the current generation of consoles, XboxOne and PS4.

    As a general case study lets take Forza for example, I would like to know about polycount in game and selection screen, shaders/materials, LODs how many, collision set up, rig set up and so on.

    Feel free to have your best professional guess as I appreciate we may not be able to get official statistics.

    forza5_carreveal_ferrari599gto_week3_wm.jpg

    Also I love this bake down by Simon Fuchs - http://www.simonfuchs.net/folio/

    1.jpg
    7.jpg
    8.jpg
  • littleclaude
  • Quack!
    Offline / Send Message
    Quack! polycounter lvl 13
    HAWK12HT wrote: »
    I think check CGCars or SMCars.net. As for me getting close to EA is in terms of maximum details within 30k with all interior exterior wheels etc :D, thats why im keeping it way to low in polys and only chamfering or adding loops on KEY signature elements of the car :D. oh btw GAME ON :P
    (i ll let u win this time, im busy with other stuff lol)

    GT5 Cars were about 100k total. That is inside and outside. So for the full car on the ps4/pc/x1 it would easily be double to three times that *if needed*. At some point diminishing returns is going to kick in and the smoothness will plateau for most cars, if it hasn't already.
  • futao
  • littleclaude
    Offline / Send Message
    littleclaude ngon master
    @Quack, thank you

    Could I have a rough polycount for these games.

    Project CARS
    Forza Horizon 2
    F1 2014
    Wreckfest
    Crew, The
    Driveclub
    GRID Autosport


    Project CARS

    Runs at 60fps on PS4, But Not on Xbox One
    Each Car in Console Versions Has 60,000 Polygons
    PlayStation 4 Handles Project CARS at 60fps, But Xbox One Currently Doesn’t – Cars Have 60K Polygon Count on Consoles
    PC has 300K Polygon Count

    "it has been confirmed that each drivable car in the console versions of the game has about 60,000 polygons. On the other hand, cars in the PC version of the game running on Ultra high settings feature polygons between 200,000 to 300,000, and the number comes down to 60,000 when the game is running on high settings. Project CARS comes with normal maps to cover up for low polygon count on consoles. If compared to Driveclub, Sony’s upcoming racer has about 250,000 polygon count per car, but the game has been designed to keep the number low at the same time."

    Read more: http://wccftech.com/project-cars-60fps-ps4-60000-polygons/#ixzz3eUTEKYjl
  • Shrike
    Offline / Send Message
    Shrike interpolator
    Edit: nice necro guys : P

    So are people modeling them subdivision ready and they are subdivided in runtime ? Wouldnt that make sense from a memory standpoint over saving out and importing the various versions as you had only one mesh at a time and save on the other LODs?
  • Noors
    Offline / Send Message
    Noors greentooth
    I highly doubt it. In the end you'd still have the subdivided mesh + lod mesh in memory. And a poorly optimized HD mesh.
    Looking at the first screen, it's clear they use custom vertex normals. So maybe they are degrading from a CAD model, or use something like meshfusion.
  • sanjeevsaiyan
    Hi, i am currently working on creating a 3D environment of a f1 garage. There will be 2 f1 cars in the scene. I am wondering if anyone can tell me in bit more depth what you mean by 60,000 polygons? 

    Does this mean in tri's so it would be 60k tris or would be 120k tris? 



  • ZacD
    Offline / Send Message
    ZacD polycounter
    Polygons typically means quads, so 120k tris. 
Sign In or Register to comment.