Spherical Projection Mapping?

#1

Hello,

I would like to create a fairly crude planet Earth. I have a seamless texture map and a sphere. The problem is, I would like to use spherical projection mapping, but I can’t seem to find this. Trying to map a sphere with planar projections is pretty difficult. Am I missing something?

Thanks for any suggestions.

#2

you have to makk a cut to divide it in half i think

#3

Thanks for the suggestion, that’s what I’ve been trying as a workaround - loop-cut the sphere in half, then map the top and bottom hemispheres. The only problem is, I can’t get enough precision on the texture maps to avoid a nasty seam running around the equator. If this is the only way, I’ll just keep fiddling…

#4

Why do you care which direction the seam runs ?

At the equator or along the international dateline ? Sure, one seam is twice as long as the other, but in practice if you can hide one, then you can figure out how to hide the longer one.

My guess is that you have some textures that want the cut along say the international date-line or similar.

#5

Why do I care where the seam is? I don’t think you understand my question. The seam lies where the two texture maps run against each other. There is a mismatch because it is very difficult to align the texture maps with any precision using this method. With spherical projection mapping, the UV Map would look like a uniform grid, making it easy to apply the texture. So far, I have only been able to generate distorted UV maps, making it hard to apply the planet bitmap. Hope that clarifies my predicament.

#6

Hi there,

Unless for some reason you need to be using spheres and spherical mapping,try using a smoothed box with a planar mapping,that way the Uv coordinates are much easier to organize and the polycount,if important to you,is kept low. :slight_smile:

#7

I just forgot that AutoUV might cleave the regions in such a way that there is no symmetry commensurate with having been created from a sphere. I’m going to have to try an chop up a sphere myself.

Yes, if you are applying a pre-existing planet bitmap … you definately need the traditional spherical mapping.

Do you own UltimateUnwrap ? It’s cheap (30.00 US) and very nice.

#8

Hello again,

Been away all weekend so sorry for the belated reply. I did find a way of doing it… by starting with a cylinder, mapping the Earth bitmap to the cylinder and then relaxing the mesh to create a sphere using the tighten command repeatedly. It’s fiddly, but it works. I’ve only just started using the AutoUV tools, so still playing. Haven’t tried UltimateUnwrap but I’ll look into it, thanks.

#9

Is this the kind of spherical mapping you were looking to achieve?

#10

Hi SpellJammer,

No, not really. What I had was a rectangular bitmap specifically designed for spherical projection mapping - so that map wouldn’t really work. Thanks anyway!

#11

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