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3D Modeling Process Thread

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  • #38752
    Max
    Participant

    Made a quickie broomhandle Mauser like the OG rocketeer carried. This is pretty much it for the model, so next up is laying out the UVs to get ready for the texturing. This is by far the most tedious part of making 3d models, so we’ll see how long that takes:

    #38753
    M
    Participant

    Great, the next steps are probably less known to people.

    What’s with the green outline on the gun? Is it something to do with having it attached to the model but still removable? I pretty much wasn’t sure how character’s equipment is typically done (i.e. if you just screw them into the skeleton in code or if you can already define them at this point).

    #38754
    Max
    Participant

    The gun is green because I happened to have it selected when I did the screen grab. You can do equipment a couple ways. In the context of a game, you will typically have a joint or socket of some kind in both the model and the gun at the place you want them to connect, and then they will be parented in code. Since this character won’t be going into a game engine, I’m going to put the gun right into the rig I’ll be using to pose him. It can be a challenge to share animations across similar weapons if the hands don’t attach in the same way, so if it is possible to model them with similar grips and stocks, you’ll save animation effort down the pipe.

    #38756
    M
    Participant

    Yeah, that’s what I thought, thanks. Just threw me off with the coloration.

    #38763
    Max
    Participant

    Next step is preparing the model for texturing and rigging. We need to lay out the UVs so that the 3D character’s skin is translated into a 2D representation allowing a texture to be applied without stretching or compressing. Think of the classic Mercator Projection map of the globe, or like a bear skin rug (not the Flame On kind, but the hunting lodge kind). Your vertices on your 3D model live in X,Y,Z coordinates in the scene, and you have to go into the UV/texture editor to transfer them onto a 2d U, V coordinate plane so they can be manipulated in an image editing program. As you create your model, the geometry tools are usually set to create UVs by default. If you create a primitive object, like a sphere or cube, the default uvs are usually something you can work with. As soon as you do anything to change the model, you are pretty much going to have to manually get in there and fix them because they’ll look like this:

    You’ll notice that the hand looks pretty good though, since it came from a model that already had all the UVs laid out. This is another advantage to borrowing bits from your library of completed stuff instead of reinventing the wheel.

    #38767
    Max
    Participant

    If your object is simple enough, Maya does an okay job of automatically creating UVs. Here is what the helmet with no piping looks like when you use CreateUVs->Automatic Mapping:

    You can see a little better that there is a face happening there, but there is still too much fracturing to be useful. You can stitch together the UVs that adjoin, and I’ll often use this method (auto create, then manually stitch) when doing hard surface objects like vehicles. We can do a little better on this helmet though by doing a cylindrical map:

    Initially that may not look like an improvement. What I need to do is decide where I want the seams to be, because there is no way to keep it all sewn together and not have a ton of distortion. I’ll grab an edge starting from the top and going down the back, then do a Select->Convert Selection->to UV in the scene window. Then I’ll go over to the UV/Texture editor to separate the selected UVs. Then I’ll cut the faces off the “chin” area under the lip of the mask and use the Unwrap tool to make them lay out with a minimum of distortion. In the event you aren’t sure which UVs connect, you can select them as Vertices and all UVs that belong to that vert will show up as yellow (in maya). You can select UVs or Verts in either window and they will update in all views:

    #38768
    Max
    Participant

    Your goal with this process is to get the least amount of distortion balanced against seams that are going to be as easy as possible to work with. To aid this process, you can apply a grid texture of some kind (I’m using the built in black and white Checker grid, but I’ve seen people use others) that will let you see where your seams and distortion are occuring. You then push and pull your UVs around until you’re happy with whatever compromise you come up with. I have the UV map blown up much larger during this process than I will in the final layout so that I get a crisper checker pattern. You can see that I’ve split the back of the helmet underneath the dorsal fin so that the seam will be mostly obscured beneath that piece of geometry:

    #38770
    Max
    Participant

    If you have parts of your model that are duplicated geometry (even if they have been scaled up or down), it behooves you to UV one of them, then duplicate it. The mouth slots on the helmet and the buttons on the jacket meet that criteria, as do the slats on the rocket pack intake. There is a tool in Maya that allows you to transfer your UVs from one identical object to another as well, but I don’t know if that is something other modeling packages have or not. If you plan to take your model into a sculpting package like zBrush or Mudbox, you won’t be able to have your UVs overlap or be otherwise stacked (you get an error on import), but once you get your normal map you can edit it in photoshop to get a more efficient use of your UV space by stacking identical elements. You also can’t have overlapping UVs if you intend to bake your Ambient Occlusion. You usually don’t want to be baking occlusion on objects that are dynamically lit, since it basically amounts to painting your shadows right into your texture. If you have an item that doesn’t move, like something in the background of a scene or environment, you can be more efficient with your draw calls by having it be exempt from dynamic lights and doing an occlusion bake. I might do that to the piping on the helmet, you sometimes see it done on armored characters to accentuate the creases in the armor plates even though they’ll be lit in realtime.

    #50617
    Max
    Participant

    Thought I’d mess with this some at lunch today, and discovered I don’t have the Maya file on my external hard drive, so I’ll have to get it from my computer at home. Has it really been a year and a half since I last worked on this? I hope @M hasn’t been sitting around for the last year and a half waiting to see how the UVs turned out…

    #50618
    M
    Participant

    @Max

    I’ve kept a tab to refresh every day, of course.

    Well, ok, I forgot too, but this is a great topic.

    #50619
    Max
    Participant

    jurassic bark

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