Car Modelling

Discussion in 'Car Modding' started by Mr.Ferret, Apr 24, 2012.

  1. Mr.Ferret

    Mr.Ferret Registered

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    Hi guys im working on my first car model for rfactor and have a couple of questions.

    Ive heard multiple smoothing groups aren't supported and was wondering how to get around this, i have heard of people saying they detach each part separately. Now i see that bumpers and doors etc are separate objects for damage that makes sense but if you need say 3 different smoothing groups to get a edge in the middle of the door for example. That would mean you would need to break your door up into 3 separate things?! i can see this model having a huge amount of separate objects if thats the case, i dont even want to think about how this would effect the already frustrating UV mapping experience.

    Thats the other thing from other game modeling and things ive done its always been one object, one uv map and a set of texture maps. How does one uv map the whole car if its separate objects, and if you need to optimize to create the different LODs does this mean you need to re uv map it again for the lower poly LOD?

    Also what sort of poly count are we shooting for in Rf2 with all wheels and cockpit? (another question with cockpit, do we have a separate player cockpit and then like a lower poly one for external viewers thats in the car or is it all one in the same?)

    PS: With the poly counts and wheels, are they instanced at all or does each wheel take up however many polys it is times 4?

    Cheers guys would love some clarification! i cant seem to even find any rf1 tuts on the modeling techniques (plenty of exporting etc, another hurdle for later im sure!)
     
  2. Johannes Rojola

    Johannes Rojola Registered

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    You detach the smoothing groups as "elements" not objects. You still have one object, which is consisting several elements. It doesn't make the unwrapping much harder. I always model cars using multiple smoothing groups, and I only detach those groups last when I believe the car is completely finished including texturing and shadow mapping. rF2 supports Max normals which means you can use multiple smoothing groups, but it is said that it is not so good performance wise so you should use regular gMotor normals which only works with single smoothing group. But this is good because you can check your car in-game while working on it.

    For LOD's, you can use the same texture. This is also how it should be made performance wise. You just edit the original high poly model so that you remove excess edges or use other optimization means. But it is hard and boring work if you want to make it well.

    Download the car making tutorial pdf from rF2 tutorial thread. There are some ISI example poly counts listed which I can't remember right now. I think we have separate cockpit for exterior and interior views, I yet have to find out how it should be built in GEN.

    All four wheels are separate, so they are not instanced.
     
  3. Mr.Ferret

    Mr.Ferret Registered

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    Thanks a lot johannes, also i didn't realize i posted this in the rfactor 1 forum im looking at rfactor 2!
     
  4. Kristoff Rand

    Kristoff Rand Registered

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    you posted in the rF2 forum... you're in the right place.
     
  5. Mr.Ferret

    Mr.Ferret Registered

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    I had tim move it for me :)

    Also another question. Is turbo smooth frowned upon for this sort of modelling or is a high polly mesh with seperate smothing groups the way to go or does it really matter?
     
  6. Kristoff Rand

    Kristoff Rand Registered

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    I'm no expert, but from what I've seen quad and separate smoothing as many polys as you need, don't go totally crazy.
     
  7. mianiak

    mianiak Registered

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    Mesh smooth and turbo smooth are going to add un-necessary poly's, so you don't want to randomly do it over the whole car, you only want poly's where they are needed, adding in extra polys randomly 'is' frowned upon, let the smoothing do as much of the work as possible, only when you get kinks and bumps is when you want to add in a poly (if that makes sense)

    However, I find that using meshsmooth (I prefer meshsmooth personally) in sections and not the whole car can be beneficial. Here is an example of what I mean http://youtu.be/kILAqOt3JK4?t=4m57s

    I also prefer making edges out of the 3d model instead of separating smoothing groups, here is a good tutorial about it http://www.game-artist.net/spotlight/MakingOf_Nismo.pdf

    But,,,, before you go and make these edges, after you have finished making the model in preparation to add the edges in, duplicate it and do the separated smoothing groups on that, this will become your lod b

    ie,,, (not a perfect example, but it should give you the idea of what I mean)
    Lod A
    [​IMG] [​IMG]

    Lod B
    [​IMG] [​IMG]
     
  8. Rantam

    Rantam Registered

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    Very good piece of information, thanks Mianiak. And the video & pdf worth the watch/read also. Thanks for sharing! :)

    Regards
     
  9. Mr.Ferret

    Mr.Ferret Registered

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    Ok i see, so make the model fairly detailed as is with a smoothing group, then go through add in your hard edges, your door / hood seams and mesh smoothing for the HQ version and the original is your LOD B and i assume for lower lods just run it through optimize a bit correct? is there a set distance threshold for when different lods are used? And with from what i can tell you just select a few polys apply the mesh smooth modifier and then collapse it down? this makes a lot more sense now compared to what i had originally heard.
     
  10. mianiak

    mianiak Registered

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    Multirez is a better option for reducing lods, also take note that I said those pics aren't a good example, if you open one of each lod in separate tabs and flick between them, you will notice a huge difference, they are pretty old pics and the 2 models are very different. To do it properly I would have the same base poly structure with the only difference being the edges.

    Once you get lod A and B done so there is not much of a difference when switching, you then take lod B and run multirez over it. There is no need to worry about where verts end up, you will get some irregular vert placements that might make you think it is unbalanced, but you mustn't go and manually edit them because that's when you will see major differences when the lods switch. If you find they need editing then you have used multirez too heavily and need to go back and re do it with a lighter touch.
     
  11. Mr.Ferret

    Mr.Ferret Registered

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    Ok multirez is fairly cool i wasn't familiar with that.

    Im on another snag with my model, its a yet unreleased car, there aren't any blueprint photos to run off though, i did have enough pictures to set up the front left right and back views, but now top, its making it rather hard to get the nice smooth curves right, so i might put it on hold until i can get my hands on a model kit (which i want for this car anyway :) )
     
  12. Mr.Ferret

    Mr.Ferret Registered

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    86 bumper.jpg

    Made some progress found a top shot from a brochure had to do some photoshoping to make everything line up and it still isnt perfect but im making some progress.

    This is the real one for those who don't know

    HTML:
    http://www.netcarshow.com/toyota/2013-gt_86/1600x1200/wallpaper_06.htm
     
  13. Mr.Ferret

    Mr.Ferret Registered

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  14. mianiak

    mianiak Registered

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  15. Mr.Ferret

    Mr.Ferret Registered

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    ah, there ya go. However some of the lines dont look right compared to my other pictures and there is no top view still...hhmm.

    i may persist with what im doing at the moment until i can get a model kit, use this as practice then start again properly.
     
  16. mianiak

    mianiak Registered

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    Ok, no worries, Just one more thing came to mind. Sometimes when I get stuck like this, in PS, I place the blueprint over an image and multiply blend it, then I lens distortion/resize/warp/rotate/etc the image until it lines up better with the blueprint. Then you will have a better idea on exactly where things go. Also if looking for photo's, if you can get one that's taken from a long distance away but zoomed in, you will get less curvature and it will be easier to line things up.
     
  17. Johannes Rojola

    Johannes Rojola Registered

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    Guys, do not always trust on "blueprints". Quite often they are wrong. There is one particular case of first gen Chevy Camaro which I have seen incorrect blueprint circulated a lot in the internet. Models made with that blueprint which are incorrect as well.
    [​IMG]

    Blueprints should be called blueprints only if they are official factory documents, but its highly unlike to come across such documents ever. Even marketing material blueprints are often off.
     
  18. mianiak

    mianiak Registered

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    True, sometimes its even noticeable that a blueprint is made from 'tracing' pictures or the scanned image from a model is slightly crooked. This is where research comes in, you usually want to spend a bit of time, trying out a few different blueprints, building a basic shape of the car to see how it looks and comparing the dimensions to real data before you commit to the project.
    The car I'm working on atm has been a total nightmare, not one single blueprint has lined up, everyone is wrong. So it's been a matter of taking a piece from here and a piece from there and putting them together until they start doing what they should.

    But the bottom line the blueprint is just a guide, after the shell has been made you do manual tweaking anyway. Getting in the mindset of a panel beater with a hammer and dolly is a good thing. (This is why I like to build the basic shape as low poly as possible to start with, it makes it easier to adjust things to get them to look right. Nothing worse that finding you got something wrong then have to move and adjust a few dozen poly's to get it right :D)
     
  19. Mr.Ferret

    Mr.Ferret Registered

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    Your not wrong with the panel beater metaphor lol.
     
  20. Johannes Rojola

    Johannes Rojola Registered

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    Yes, this is pretty much the exact workflow which I have too :)
     

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