Help With UV Map Please!

I have a model of a building - to exact measurements.

I created the UV Map and you can see the result here

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Why do the sizes and shapes of the islands in the map not reflect the model exactly?

The front face in the model is the top left island.

If I apply a texture to it (the actual face has words as well as colour) it is the wrong way round i.e. as if it has been squashed from left to right

Is there any way of ensuring the islands have the correct aspect ratio?

regards

alex

Hi !

Try to check correct aspect when unwrapping :

See you ++
Tricotou

Hey. Did you apply scale before unwrap?

I have that checkbox in Smart Unwrap and it is checked

Regards

Alex

Not sure what you are asking here, sorry.

Regards

Alex

Blender warns about non-uniform object scale but the warning is easy to miss. Apply it with ctrl+A -> scale, in object mode obviously.

But as the model is made of almost completely out of n-gons, which are faces with more than 4 sides, it’s not a surprise there are problems. Blender and other programs don’t do well when unwrapping n-gons, especially concave ones

1 Like

Well, that’s neatened up the map

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but I still have the orientation problem.

the front face of the building is the island now at top second from the right.

It is not, however, the correct way round. The left and right sides of the rectangle are in fact the left and right sides of the face in the building (not what i would expect looking at the other islands)

So when I apply my text, it runs up and down the face rather than along the top

So although Blender has appeared to maintain the aspect ratio, it has done it with the wrong orientation

Regards

Alex

The orientation of the uv island does not have to always obey with the 3d model. The important thing is that it remains in 0-1 uv space( for your purpose now).
To actually get your desired orientation you have to manually select the face and press L to select linked faces and manually rotate them.
You can then select Pack UV islands under UV menu and uncheck rotate islands.
This should preserve the orientation of islands and match with model.
Automatic packing most of time never gives desired layout, so there is always manual labor involved.

So close…

The answer was " In Object mode, select the Object and press Ctrl+A. Select Apply > Rotation & Scale."

The ‘wall’ is now in the correct orientation and with a slight amount of adjustment, I can add my texture file correctly.

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Thanks to all who tried to help

Regards

Alex