I'm currently writing a space game that has 3D planets in it. One of the problems I'm having is that the sphere pinches the texutre at the poles. I am using TrueSpace 6, and I use their Sphere UV map and I've tried both their regular spheres as well as the Geo-Sphere, with no luck so far. Does anyone have any idea what I'm doing wrong? Is this a problem with my model, or with my texture? For right now I rotated the sphere 90 degrees to make the problem less apparent. Here's what the problem looks like: Thanks

You could use a cylindrical UV map.

Read this(go to section 2.1):
(Celestia is a space simulator)
http://www.lns.cornell.edu/~seb/celestia/textures.html

The spherical map (as well as the cylindrical map) will generate those kinds of pinch points at the poles. There's not a whole lot you can do about it. If your texture coordinates at the pole are welded, you can make it slightly better by splitting the vertex at the pole, such that each triangle leading up to the pole gets its own texture coordinate at the pole.

A better mapping is typically cubic (box) mapping; it maps 1/6th of the sphere to each of a cubic area. Then you can put those 6 faces into a single rectangular texture, and it'll be somewhat better. You have to work pretty hard to make the seams line up, though.

if your painting your textures in photoshop you can sort this by carefully making sure the texture matches where the seams join. As your texture is simple this would be easy.

Think about how the cordinates are mapped and you will understand why you get this problem.

Thanks everyone... I still haven't had much luck, but I think I need to play with my texture to that the poles are more uniform. I think the color at the top of my texture is too varied. I am going to use cylindrical projection. I tried playing with the cube projection for a while, but it was just too hard to get the seams to line up.

Thanks again.

The type of mapping you're talking about is called "equirectangular projection." A proper EP map looks stretched at the poles, like this:



So when you map it onto a sphere, the stretched portions neatly come together to form a clean surface map, like this:



How you stretch your textures is entirely up to you, but I'm sure you could find some software to do it for you.

(The above texture is property of 3-D Software, used without permission.)

I agree with the unwrapping solutions. I use TrueSpace 6.6 with the gamepak 1.6 to make all my game's models and textures. The UV editor will allow you to unwrap the sphere into a classic flattened-globe texture to create a decent looking planet.

What you should do, is paint each Longitudinal section of the sphere a different color, then apply the box UV projection. Then, open up the UV editor and use the buttons at the bottom that allow you to cycle through materials. grab each longitudinal section, separate it, shrink it slightly, then move it around until you have the whole things layed out in a way that makes sense. Export the bitmap to a photo editor, and paint your texture on.

It will take time and tweaking in both apps before it's just right, but it can be done and look pretty good.

Quote:

Original post by DrewCaliburClark I agree with the unwrapping solutions. I use TrueSpace 6.6 with the gamepak 1.6

Is it worth the price to buy gamepak? I thought it was primarily for mods.