Subdivision and UV Unwrapping


Ok, so I have been fiddling with Blender for a few weeks now. Walked through BlenderGuru beginner tutorial with the donut and coffee mug, then I just jumped in trying to figure out just modeling and texturing for game design.

I was messing with a building idea (moreso learning how to make a building) and I noticed that I get unexpected curves in square/rectangular faces when I unwrap. Here is what happens, maybe someone could explain a better approach.

  1. I create a plane, and size it to the full size of the house.

  1. I enter Edit mode, and extrude it up to build a foundation, and subdivide the top to build the walls, then I extrude that up as well.

  1. I select the faces of the foundation, mark seams, and unwrap. The result for the squared/rectangular objects unwrapping also includes some unwanted curves. Applying textures causes them to warp in those curves.

Now, this time I replicated the issue, I did not include my doorways, which made the curves much more pronounced. I noticed that if I do not subdivide, the sides can be selected, marked as seams, and unwrapped with perfect rectangles. After a subdivision on that top surface, even before extruding, it will skew the UV Unwrapping.

Any better ideas for modeling quick houses with Edit mode and UV Unwrapping easier?

3rd screenshot, the selection contains n-gons which are faces with more than 4 sides. Those are prone to distort when UV unwrapped. Commonly known thing not only in Blender but also in other programs.

If the n-gons are planar, convex, and can be left in a model, there are ways to work around the unwrap issues, but that’s not a smart place to have them. Make one without. The floor is also unnecessarily subdivided.

There are multiple workflow options. Floor and ceiling can be separate geometry/objects, planes if the exterior shape is rectangular. The walls you could build like you were going to by first making a floor plan of sorts and then extruding up. Or, could also use edges to build the exterior walls and use solidify modifier to get the thickness after extruding, and interior walls would not connect with exterior walls, just intersect them.

Separate geometry helps unwrapping. Whether or not to connect the walls depends on what kind of textures they need to have as a pattern can’t be seamless between two walls if they just intersect.

If you use solidify modifier for the thickness, you could start adding cuts for doors and windows after the walls are already up. Once the walls are done, could add seams, make a backup copy and apply the solidify modifier to make the geometry real, then delete faces that are not seen. Those are faces below and top, and faces that are inside other walls. Deleting the faces separates the parts and opens up geometry for ones that intersect, which means less seams and easier unwrap.

There are also addons you might want to check at some point. Archimesh and window generator for starters.