3D sphere - How do I fix this seam on my texture?

Hi TD-community!

I’m playing around with some texture on a simple 3D sphere thing and I can’t really seem to fix the seam with the texture SOP. As always any help, advice, comments… is welcome :slight_smile:

Circulating round thing.toe (5.4 KB)

This has to do with your choice of uv map algorithm. Equirectangular Outside (Spherical Polar) with the Projection Axis set to Z, must choose a longitude (or is it latitude…) where it must create a new seam. Because it’s choosing to make a seam between two connected edges where there are faces, you get some extreme stretching, as the texture from two totally different parts of the uv map are interpolated:


Here’s what the uv map looks like with that UV method. The green lines are the faces that make up that stretched region.

Here’ I’m morphing between the physical coordinates and the uv set for illustration.
uv mapping seam

There’s no real solution to this but to change the uv algorithm to something that unwraps the sphere along it’s existing uv seams, but then you’ll still need to tile it.

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Hi Lucas,

Thank you for your extremely well formulated answer! (with animation even!) :slight_smile:

Do you know if there’s a way to create a tiled 2D UV-map and wrap it around the sphere so that it fits with no seams - or am I understanding you correct here?

Or actually I just have to make a texture which is of a seamless tiles-pattern - or?

Spheres are tricky. the default uv’s for a sphere in TouchDesigner are that of a UV sphere, where uv’s follow a longitude/latitude type of structure. This is easy to tile, and minimal seams, but the poles get stretched. Increasing subdivisions a lot helps, but in the end your texture has to be pre distorted somewhat to accommodate the poles.

There’s probably some good reference on the forums for uv mapping for projection domes, you could go down the road of taking 2 180 hemispheres with a more robust uv mapping and join them together, you’ll just need to make sure you are handling that extra seam somehow!

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Nice! Thanks man, appreciate all the advice.

I was also wondering if this type of pattern-effect would be easier to accomplish with instancing?

I’m still a rookie in TD and I haven’t really been messing with instance enough just yet, perhaps it’s something for me to look into with this.