Repeated Elements on a Building: Which workflow is best in Blender?

DDevilfish

Hey polycount people, first post here. I'm in the process of strengthening my portfolio a bit before I send it out to local companies, so I'm rapidly reaching into things just a bit beyond me. I'm just finishing a university degree, but courses on 3d and art in general were pretty basic, so I'm 99% self-taught and muddling through. Please excuse any obvious foolishness that might've be related. I've found lots of info for different methods of texturing repeating parts, but I could use some advice on which method is best for this scenario before I waste a lot of time trying them all.

I've modeled this city building and there are a ton of repeating elements. I'm planning to use Blender's materials system and bake the texture maps, but the model is complex enough that I'm worried about texture space efficiency. This won't be used in anything, but I'd like it to be done with game production in mind. The model is currently all one object except for the windows, and if possible it should be just one 4096x4096 baked texture in the end.



- I assume I should stack the UVs for repeating elements like the window frames. Correct?
- I want to use the auto-unwrap once my seams are marked, but I don't think it would leave any UV islands stacked... should I delete all but one window frame of each type, unwrap, and then duplicate it to replace in all the deleted ones?
- Or should I link object data and texture them that way? It would seem efficient, but will it still auto-unwrap as separate islands, thus not solving the texture space problem?
-Other methods?

Thanks for your time!

frmdbl

First off, I if you have repeating elements that are identical you should keep them linked, so you can edit them all at once. I think this is just common sense.
They will share all of the mesh data including UVs so you'll be able to bake just one of the instances and the rest will use the same texture/material setup.

Looking at the model you could split it into modules/parts and bake them. but it seems like there would be quite a few different pieces, so that could take quite a lot of time.

I think the most efficient method and one that would give you relatively good quality would be to use a trims/panels texture (or a couple of those) and map it onto the mesh.

DDevilfish

Thanks frmdbl, yeah that'd probably be simpler, and I -did- ask for the most efficient way. But another day of experimenting and research has turned up a few things, most notably the actual terms I should use to describe what I'm trying to do. Procedurally generate textures and bake them into one image for the whole model. I set out specifically to learn how to do this, so I'm pretty locked into it, even if it takes longer.

What I was more confused about is how to correctly/efficiently handle all the repeated elements... As you point out, I should have had each window as a separate object and remember alt-d, not shift-d, in the first place. I could have linked object data as well after the fact. What vexes me though, is what happens when I join them into one object with the main building again. If I repack the uvs with ctrl-p in order to fit them in, it will un-stack all those repeating elements. I know this is technically fine with procedural generation, but the smart uv project results are so horrendously wasteful with the number of repetitions in the model.

My next idea was to delete all but one of each repeating element, as theyre all snapped to the grid so easily replaced... I think if I unwrap everything this way, I can then duplicate everything in edit mode without disturbing the uvs again. Im pretty sure itll work, but there must be a better way...

Mirbobo

Is there a specific reason why you need to attach/combine the meshes together instead of just keeping them as separate objects? Iirc it's complicated or impossible to adjust UVs of multiple objects by default in Blender, but there should be a plugin of it or things might have changed since the last time I used it. Also in a game production this would most likely be built in a modular fashion, unless if it's for a top-down game, RTS or whatevs.

Also you haven't really given a real definition of what your end goal will be, is there a specific reason you want to pack everything into a single 4k map? Current gen game asset would generally use multiple tiling maps along with trims sheets and uniquely textured elements for a building of that size.

RN

If you plan on baking lighting such as ambient occlusion and a lightmap, all those repeated elements will need to have unique (non-overlapping) UVs.
If you're going to use it in a game engine such as Unreal or Unity, they have their own lightmapping tools in there where you bring in your UV'ed mesh and then bake it with the lights you have setup in the engine scene.

DDevilfish

Helpful replies, I think I've got what I need now. I did have a good reason to do it this way: One of the companies on my short list, where I have connections, apparently does this all one object, one texture thing for their main game assets.

But a lot of you are mentioning it's weird to do this on an asset of this size/detail, which is exactly what I needed to hear, so Im glad I asked. That company does city builders, and most buildings are a -lot- less detailed or closely viewed... so I was starting to suspect I might have just taken this too far for that workflow.

Guess I was just trying to kill two birds with one stone: Look, I can do your workflow! But at the same time, tiny city builder buildings don't exactly fill a portfolio, so I went bigger... maybe I should just make a whole city block in their style instead. I'll split this into separate objects and just let it be it's own thing, and do something else to catch their eye. Much obliged everyone!