Unable to Project a Spherical UV Map Like this

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#1

I am creating a displacement thumbnailer and need to UV map a Sphere in such a way that it looks perfect on one side without poles. I could care less how the backside looks since the mesh will only be rendered from one angle. Example image: https://i.imgur.com/lPHuxKJ.png

I have what I need but the mesh is triangulated and I’d like to find a way to accomplish this myself.

Here’s what I am looking to re-create:

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The closest I can get is camera projection in blender, but I can’t come anywhere near to what I need.

Any advice GREATLY appreciated.

#2

I am not sure if this is exactly what you are looking for, but by using mapping/texture coordinate nodes and using an object as a reference, by scaling and moving the reference object around I have been able to get something similar.

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sphere.blend (779.1 KB)

#3

Have you tried this:

On this subject however - does anyone know why the UV sphere doesn’t unwrap correctly.

Seams are (I believe) supposed to represent cut marks on the UV map, however if you mark a seam on a UV sphere, then do a sphere projection, the resulting UV map is all over the place.

Why are the triangular faces offset to the right - and why does one of the square faces also get placed on it’s own over to the right - leaving a gap where it should be on the left? Why aren’t the faces adjacent to the seam at the edge of the UV map (e.g. the selected face highlighted).

Is this just a bug that has never been fixed?

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#4

That’s not a bug. Projections don’t use seams.

#5

Ok fair enough - but is that really the best outcome from a projection. It seems very unintuitive and somewhat illogical.

#6

Try a rounded Cube instead…Here I worked up a quick example…rounded Cube 5 subdivisions. Face> Tri to Quads…UV= Spherical Projection.Align to object.Polar z-y> correct=Clip+scale. Constrain to image Bounds…

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#7

Sphere Projection seems to work fine in the last Blender version:

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#8

Found a solution on StackExchange: https://blender.stackexchange.com/questions/203781/how-can-i-achieve-this-type-of-spherical-unwrapping

It involves distorting a sphere, projecting a new UV map from the camera to the distorted sphere, and then transferring the UVs from the distorted sphere to the clean one.

It’s a great way to make “Thumbnail Preview” images since you can avoid the typical stretching and ugliness from UV poles.

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