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Noob at Trim Sheets, seams, and unclear best way to setup uv's [Blender/Unreal]

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aphixe null
I am working on a building in blender for a level I am making in unreal. I designed my trim in Quixel mixer using mask's and mega scan surfaces. I'm getting obvious issues are the seems. my biggest issue is lining them up and all. It is a uv problem, but could also be a design of my trim sheet's as well. Right now my mesh is 400 by 400cm. everything is snapped to the grid. The height of the trims might be an issue as well as texel per say. inside blender I have textool and I was working with scale on the bricks and set them to 205 texel. maybe i should of used 200 but I clearly need to learn a lot more on quite a few subjects here. I guess a lot of this project is me very lost. I have a vision for the building based on some images of real buildings.

If i had to sum up my questions, they would be what is a good way to get tiling to be good and reduce seams, how to properly know what texel setup I would use, and finally best practices when doing trim sheets, as I feel I am lost on the manner. The content I found so far is how to bake a complex trim sheet with zbrush and the like but perhaps rules to follow would help me here.

Thanks.



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  • icegodofhungary
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    icegodofhungary greentooth
    See that little bit of a polygon hanging out in the gray area for your brick texture? That's what the seam is. It's wrapping around to the other side in the middle of a polygon. Your texture isn't perfectly tileable. If it were, there would be no seam there as the edges of the texture would match up. I never used Quixel so I'm not sure if there's some way to make textures tile. The seam on the white part may have the same issue, as I see part of it hanging off as well. But it almost looks like there could be 1 or 2 pixels worth of padding between the edge of the UV space and the texture there. So double-check your masks.

    Here are a couple of good, general tutorials on trim sheets, you may have watched them already. Even though he uses zbrush to create his trims, the way he plans out and applies his trims his universal.




    And here is the thread on it if you need to ask questions about the tuts:


    The general rule for texel density is 512x512 per 1mx1m. But with trim sheets, your density won't be entirely consistent, especially if you're using them on a variety of different sized objects. But 512px/1m is a good guideline for contemporary games. If you're doing a first person environment, you may do it 1024px/1m in areas that are very important and take up a lot of screen space. Your character will be roughly 1.5-1.8 m tall. I would suggest finding a mannequin model, you can rip them out of unreal, and always having them in your scenes. Both your unreal scene and when you're modeling in Blender. This helps you keep things in proper scale. You can also use them to compare texture scale. 

    You should have some bevels in your trims as well, as these let you fake a baked look. Your edges are pretty sharp and unconvincing, especially on the white concrete/stucco texture. You're really using that trim the wrong way by just creating one wide strip of texture. If you had a couple variations in width, and had some bevels, it would look much more convincing in the unreal scene.

    Here's a power point and video on The Ultimate Trim technique. It's for a stylized game so the bevels are a bit larger than what you would use for a photo-realistic game, but it shows just how powerful using bevels in your trim can be:



    So to answer your questions:

    To reduce seams: Make sure your texture tiles. You can do this by just changing the UV repeating in your software of choice. Each one has it in a different area so I can't give you specifics. In unreal if you apply your texture to a piece of BSP geometry, the option shows up in the details menu of the object.  If you can't find pre-made textures that tile, make your own.

    Texture density: 512x512 for every square meter in most cases. Go 1024x1024 if it's for walls/ground and you get up close to them like a FPS situation.

    Get a mannequin so you can model with proper scale. When you start blocking out bricks and stuff for sculpting your own textures, you can use these to help keep things in scale too. For example, a single brick shouldn't be bigger than your entire character. And likewise, a texture you intend for an 8m high wall shouldn't be smaller than your character.

    Trims aren't the most intuitive thing. You have to start thinking about your models in terms of texture strips. And you have to learn to turn rectangular texture strips into curves, and odd angles while looking somewhat convincing. But don't try to run before walking. if you're struggling with basic texturing, it's a hell of a learning curve. It's okay to practice making tiling textures and coming back to trims some other time. It's also okay to just make a wall and nothing else. Take little steps.

    Look at other works that use Trims. God of War III, Dishonored 2, and Borderlands 3 are the ones that come to mind right now. A lot of modern games use them, but those are the ones I can think of right now. Look at these games and think in terms of strips. You should eventually be able to start seeing how they're using trims in everything, from the buildings to the prop items. Look for repeating details in the textures.

    Screens from Dishonored 2:
    This one in particular, scroll to the bottom and see 1 2048 trim sheet and one 2048 tiling texture:

    Here's a project that uses trim and tiling textures, inspired by Dishonored:

    God of War:

    Here you can see trims used for Borderlands 3:

    Here's a good example of what I mean by learning to made odd shapes with strips:






















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