UV islands from seperate objects

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How would you seperate uv islands from seperate objects within the mesh into individual islands? I dont want every island to be combined, but also not for every individual face to be seperated by its angle. Here is a mockup of my goal.

mockup
mockup2940×1834 2.86 MB

UV smart project can only go up to 90 angles, so every section of a cube’s face is effectively separated. UV unwrap either makes the faces into this weird sprial-ish shape making 9 (or so) islands, which is less than there are buildings.

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When you you create primitives ; their UVs are automatically generated.
When you mesh edit them, Correct UVs option may be enabled in certain operators to avoid to redo unwrapping.
But you probably will have to redo some, after extrusion.

If it is needed, don’t unwrap the whole as one. Do the unwrap mesh by mesh to obtain desired UV Islands. Unwrapping operator works on the selection.
If you don’t want an unwrapping to be applied on the whole ; just select a part of scene.
Then, when UV Islands look like as desired, pack them to avoid overlapping.

Packing operator will work on the whole. You don’t need to join objects.
Multi-editing is supported. You just need to select all of them, when switching to Mesh Edit mode.
Then, you can go into UV menu of UV Editor > Pack Islands, define a margin.
And you should obtain an UVmap with same name on each object, allowing to use the same Image Texture for different objects.

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Hey, thanks so much for responding!

Sorry if I read this wrong - do I need to individually unwrap all meshes? That seems to work but it would take a while for all meshes. If that is the only way, thats alright with me, just double checking.

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I think you used something like a “city-generator” ?? I tried some simple one and TBH the UV’s which they did generate are “bad” or non-existent. If this is only for some background asset you might be lucky with some cubemapping.

In general i think it is better even for some lowpoly buildings to do some proper UV unwrapping for some types of buildings and then scatter them somehow.

Of course there are multiple city-building addons out there which can do some aspect better than the other. Not everyone can afford CityEngine:

And they even do not tell how much it costs… :stuck_out_tongue_winking_eye:

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I used a 3d model of tokyo from some google tiles downloader website using an api key, and traced the buildings with cubes (and tried my best to make a comprehendible UV map), before finally editing them to fit non-top down views, projected the textures, and went to these fourms. Thanks for the advice on UV mapping though! hopefully blender or some addon developer can fix this in the future.

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What I meant is :

  • for simple shapes that you did not extrude, you may not have to unwrap. Generated and correct UVs could be satisfying.
  • for heavily modified shapes, you probably will have to unwrap. In that case, you may unwrap as once, using a pertinent method, only for a pertinent selection of objects.
  • At the end, when you are satisfied with amount and shapes of UV Islands ; you can pack islands for the whole. That is a different step than unwrapping.
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Ah, ok! Thanks so much!