Yeah, you're right; thanks. The existence of the "Details on Discrete LOD" answered my question, although it doesn't list any examples of how it's done. The easiest way I can think of is to what I sort of described earlier and subdivide polygons, like in this example I made:
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The red is the least detail, the green is middle, and the blue is most detail. How this would be stored in memory is beyond me, especially taking into account having points connecting to other low quality points.
I see rainwarrior made a post as I was finishing this...
rainwarrior wrote:
LOD is also important for streaming data, where you load in the low LOD first as a placeholder until the high LOD version has time to load off the disk asynchronously. Again, in this case you end up having to have enough RAM to have them both around anyway, and the low LOD might be useful for the case you mentioned too (i.e. far distance draws) so you might as well keep it anyway.
I didn't think models were streamed real time; I thought they were almost always sitting in ram.
rainwarrior wrote:
2. The size of the additional data for a low LOD is usually not a big concern compared to its "big brother". If you have enough space for the full LOD, the low LOD verison is easy to manage. The low LOD isn't usually 50%, it's probably less than 25% of the data, if even that much.
Oh yeah, I wasn't thinking about that...
I do find the quality dip to be too obvious for the most part though, either switching quality too close up or only having two or so changes.
I'm getting the impression that it's better to just have multiple models made for characters, but I heard you said it can be useful for terrain. What I wonder, is do you mean just straight up montains, or for everything that isn't an object? (So 3D equivalent of a BG layer, basically.) The big thing I can think of about this is that while you can just use different models based on just checking the distance from the camera for objects, you can't do this with the background because it's both close to and far away from the camera. You'd have to have multiple layers away from the camera, each with their own LOD. I don't think the example I had shown before would look too bad here, especially considering the background is typically less complex geometrically.