Help with UV unwrapping

Hi there, I’ve been trying my hands at UV unwrapping lately. It’s intimidating but with the help of YouTube tutorials I’m slowly getting there. But as I’m trying to UV unwrap, I always ask myself if the problems I’m facing stem from the 3d model I’ve made. I’m new to 3D modelling so I’m unaware if there are certain rules I should follow while modelling.

To illustrate my point clearly, I built a low poly cottage from a cube. The entire structure has been built from the default cube except for the doors and windows. I modelled the doors/windows separately and joined them to the mesh later. Is this a proper way to approach this ? Should I leave those elements as they are and texture them separately ?

I’ve tried unwrapping the model but the results are not so satisfactory. While some sections look good, some parts look crooked and blurred. The problem lies mainly where I’ve cut holes in the geometry to attach the door/windows. I’ve tried solving the problem several times but I just can’t figure it out.

How would I go about solving this ? I would really appreciate links to tutorials or reading material to better tackle this. Thanks :slight_smile:

The solution depends on a lot of things. For example if it’s a low-poly project with a very basic material, the whole house could be one object with only one material and you unwrap the whole object. If it’s a more complicated object, with different kind of textures, it’s much simpler to give each part its own material, and therefore keep each part a separate object or at least a separate mesh to which you’ll give a separate material and unwrap separately. Maybe show some pictures of your current object?

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I either have things like windows and doors as separate items, or at least, with their own material. That way, you can have UV maps per item, not have everything in the one UVMap (unless of course, you have to for exporting to say a game engine). It also means I can control the resolution, so have a high res map for teh walls as there’s so much space, but lower for say a window. I always try to approach UVs as cutting out a paper model if possible. With houses, the walls, I’d choose seams where it was logical, like where I’d maybe have different wallpaper on different walls. Putting seams around every cutout of doors and windows as well.

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Thanks for replying. My modelling is really bad but here’s what the house looks like.

what do you plan to do with your object? is it part of an animation? will it be far from the camera, or is it for close-up shots? what is the style, cartoon or realistic? are the windows made of glass? is the door supposed to be animated? I guess the best solution will depend on all the answers…

I plan to composite this model and few other 3D elements with live action footage. I’m trying my hands at set extension and all the 3D objects will be far away in the distance.

Maybe the stuff I’m trying to do is not required and I’d be better off just projecting an image onto the 3D geometry, I really want to learn UV unwrapping. I’ve been ignoring UV unwrapping for the longest time and I thought this was a good time to learn it.

More questions:

  1. This is how the windows look from the inside. I deleted faces facing indoor hoping to get a better UV. Is this the correct way or should I have left them as they were ?

  1. The texture appears wonky near the windows. I made the hole in the wall with a Boolean modifier. What if I make loop cuts and then deleted one of the faces for the window hole ? Would that make the texture appear straight and crisp ?

you could redo it with the Project from View option, or choose a more rectangular topology like this one? it may help to have a better unwrap, you can cut the edges with the knife:


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Thanks ! Can I repeat the Project from View option separately for each wall segment ? Or will it update every time I do it ?

Have you tried the Smart UV Project option? It will unwrap according to the angles

Yes, I did try that several times. But when I took the model to Substance Painter - the textures looked all over the place. I tried tweaking the Smart UV map but I failed every time. Maybe it’s because of my inexperience.

Actually I think the bad unwrapping you are showing must have to do with bad seams

In that image, I’d personally make the roofs, overhangs etc separate objects, not part of the main structure. In the real world, that would be the case.
EDIT: A quick take on your idea, uv seams applied.
Housetest.blend (994.3 KB)

Thank you so much ! You made it look so easy … Also separating different elements from the main structure helps I guess.

For the time being, I auto unwrapped my entire mesh and then edited some portions. It worked for me in the end but I’ll definitely keep your example in mind as I build more 3D elements for my project.

More questions if you don’t mind :slight_smile:

How did you go about making the seams ? Did you auto unwrap to start with and then removed unnecessary seams ?

One more thing … In a previous build of the same house - I added a solidify modifier to the entire structure because the Boolean tool wouldn’t cut through the walls because it had no thickness. But when I unwrapped the UV map it was a total mess … It was so complicated that I didn’t fully understand it but I assume that even the inner walls were part of the UV map. I see that the structure in your example also has thickness but the UV map only reflects the outer walls. Where did I go wrong ? Am I making sense to you ?

For seams, I tend to create the structure, then think about where I would like them, before unwrapping. So where I think a seam will reduce stretching or just where I want to isolate things. I don’t think I have ever used smart project as I like to control my maps, where smart project just “cuts” them based on angle, which may not actually be what you want.
Yeah, regards Solidify, that will hose your UV map because in reailty that thickness doesn’t exist, so it tends to stretch the heck out of mapped textures. My structure, technically, doesn’t have thickness, what I did was simply extrude the edges around the openings to give the illusion of thickness, if you were to place a camera inside the building and look at it, you’d see the walls are paper thin.
If I am making a “proper” house, with solid walls, I would tend to build the walls with thickness. Then I tend to remove the top and bottom polys as you never see them. Then UVMap the external and internal walls separately. If I know my camera is only ever going to be either inside, or outside the structure, I just use simple planes as it’s a waste adding geometry you’ll never see. Unless, for some reason, I think I may re-use the asset in another scene of course.

Thank you so much for the detailed explanation !

No worries, if you want, I could put together a video of how I would do both a solid and ‘paper thin’ house and set the uv seams. Just let me know and I will get it done over the next few days and pop it on my Youtube channel.

That’d be great ! I would love that if you can make time for it :slight_smile:

Will try to get something done over the couple of days. :slight_smile:

Video is now up on Youtube, along with a link in the description to a blend file, hope you find it of use.