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Is it standard practice to separate your model at the seams for game asset creation? (keeping it as one object). Ive extracted quite a bit of game assets and they're all split up into multiple pieces at the UV seams. Just wondering if this is standard in the industry and whats the reasoning behind it?

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It's standard for game coders to not bother programming anything they don't need. One thing they don't need is face-corner data-- split vertex data. All they need to render the game is vertex data.

Your video card has no conception of face-corner data. It doesn't know this face has this UV and that face has that UV. It only knows that a vertex has a certain UV, which is interpolated across all of the vertex's faces. Yes, that means that even if you don't rip your seams, those vertices are still being calculated twice (or more) by your video card. If game developers want to handle face-corner data, they need to do that internally.

But they don't need to handle it. Face-corner data is a convenience for artists, but it's not necessary for games. If you need a UV seam or sharp edges or discontinuous vertex color, you can just double your vertices at that discontinuity. And it's trivial to build that into an export algorithm.

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  • $\begingroup$ Of all the game asset creation “tutorials” out there. I find there’s a lack of important information such as this. Love the explanation! Is there a good resource to more in depth information on game asset creation? Also, By “doubling vertices” do you mean just duplicating them or adding another edge loop? $\endgroup$
    – bonypoy
    Commented May 9, 2022 at 23:54
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    $\begingroup$ @boynpoy "do you mean just duplicating them or adding another edge loop?" Not sure the distinction you're making. It's just like selecting the seam edges and doing an edge rip operation. $\endgroup$
    – Nathan
    Commented May 10, 2022 at 2:33
  • $\begingroup$ Awesome, thanks for the clarification! $\endgroup$
    – bonypoy
    Commented May 10, 2022 at 2:44
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  • Select a seam, then press Shift G to select similar and choose Seam. This will select all seams in the model

    Select all seams

  • Press Ctrl V and choose Rip Vertices. This will separate the edges, and create overlapping edges each belonging to the different side of the seam

    Rip vertices

  • Press P to separate mesh, and choose By Loose Parts. Now you have different objects separated by seams of the original mesh

    separate by loose parts

  • Not every seam will result in a loose part. We can undo the ripping of these vertices by merging the vertices by distance

    merge vertices

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