[w i l l]

Pretty basic question - what's the best way of mapping a texture to a sphere to give minimum distortion?

i.e if I map the golf ball texture or a perforated hole texture using the spherical projectors the bumps/holes get smaller towards the top/bottom/poles. What do I need to do? Alter the map? This looks ok;

[RonB]

I don't know how everybody else does it but to make a texture for a sphere I do this: The texture map should have the aspect ratio of 2:1. It helps if the image is tileable. In Photoshop apply Filter/Distort/Polar Coordinates/Rectangular to Polar. You will have to do some adjustment and cloning, or cut and paste to fix the image in the middle, (which will later be the top). Next repeat the filter but this time use Polar to Rectangular. That fixes the top of the texture. Now flip the image vertically and repeat the process to fix the bottom. It works great for most textures. But I have never tried to do a distinct pattern like the dents on the golf ball so maybe there is a better way. I will anxiously await someone elses method.

Hope that helps some.

Cheers,
Ron

[w i l l]

Ok thanks. Well 'firebird' created this material (golf ball) so would be good to know how he/she did that.

[Maximus3D]

Maxon has a nice and pretty easy tutorial which might help you create your own spherical textures without polar distortion.

http://www.maxoncomputer.com/tutorial_d ... orialID=54

Or you could try this Photoshop plugin

http://photoshop.pluginsworld.com/plugi ... rPage.html

/ Max

[Mihai]

The simball has flat UVs projected from the cameras POV so from this angle the map looks ok. The map used in this material is a regular flat map, no distortions applied to it to compensate for the spherical mapping distortions at the poles which you will get with spherical UVs. So the only way is to use the methods described, or at least cut the UVs of the sphere into several parts so you can still use a regular flat map on it but then you'll have to take care of hiding the seams.

[leoA4D]

Thanks for the links, Max.

[w i l l]

The simball has flat UVs projected from the cameras POV so from this angle the map looks ok. The map used in this material is a regular flat map, no distortions applied to it to compensate for the spherical mapping distortions at the poles which you will get with spherical UVs. So the only way is to use the methods described, or at least cut the UVs of the sphere into several parts so you can still use a regular flat map on it but then you'll have to take care of hiding the seams.

Well i'll just project flat UV's from a plane then. i.e. like the camera POV - i've had to do that a lot before. Works ok.

[w i l l]

Maxon has a nice and pretty easy tutorial which might help you create your own spherical textures without polar distortion.

http://www.maxoncomputer.com/tutorial_d ... orialID=54

Or you could try this Photoshop plugin

http://photoshop.pluginsworld.com/plugi ... rPage.html

/ Max

I had a go with the plugin - its easy to use but its hard to get a regular texture like the golf ball one to look right.

[w i l l]

Could any clever people help me distort this map to map to a sphere (below). Tried the Photoshop plugin but it distorts the dimples. Hope someone can help PLEASE!



Here's a pattern of it;

[RonB]

What we need here is the ability to map a sphere as a symmetrical ouroboros. There are lots of different kinds but what would do it perfectly is the wrap used to cover a baseball.
A baseball uses two of these patterns....must be a way...

[ishook]

Your UVW map should have a face-map option. meaning it maps whatever the textures is to each face individually. If you make a geosphere (all equalsized triangles) then you could make a map that would look good on once face (triangle) and see how it ends up. ie: make a map with one dimple.


Does that make sense?

[iker]

as RonB says you need a map that seems like this one...


I think Richard Rosenman has a free photoshop plugin called Sphere Mapping Corrector or something like that....but I haven't tried yet.

[KurtS]

that maps work perfectly, Iker. Did you create it? Or do you know how to?


RonB: I tried the method you suggested in december, but it does not seem to work at all. At least not for spherical mapping. Or maybe I am doing somethin wrong?

I've been looking for a solution for this several times, and never forund anything useful. I'll have a look at Rosenman's plugin later.


edit: I've had a look at Rosenman's plugin, and it does not make anything like the golfball map that Iker posted.
It looks to me like Rosenmans pluging makes a map that simulates a perfect directional projection (but only when you use a spherical projection!).
Like a REAL directional projection, the Rosenman result looks good only from one POV - but not like a golfball.

[w i l l]

that maps work perfectly, Iker. Did you create it? Or do you know how to?


RonB: I tried the method you suggested in december, but it does not seem to work at all. At least not for spherical mapping. Or maybe I am doing somethin wrong?

I've been looking for a solution for this several times, and never forund anything useful. I'll have a look at Rosenman's plugin later.


edit: I've had a look at Rosenman's plugin, and it does not make anything like the golfball map that Iker posted.
It looks to me like Rosenmans pluging makes a map that simulates a perfect directional projection (but only when you use a spherical projection!).
Like a REAL directional projection, the Rosenman result looks good only from one POV - but not like a golfball.

I made a map with the Rosenman plugin but couldn't get it to look correct even from one direction. This is all I need though! Camera from the front looking directly at the sphere - can I use that plugin to 'bodge' that look? Could you help me out with a map?

[KurtS]

hi Will,

this map works fine in my 3d-app using default or "spherical" projection mode. You might have to rotate the texture 90deg (I had to), but I'm not sure how this works in your program.



Applied to a sphere it looks like this: (but only from one POV):