Pole Pinch Correction...

[Dollan]

Hey folks...

Does anyone know if there any plug-ins for Photoshop or Paint Shop Pro which would help to eliminate pole-pinching in new textures? I realize that I can fix the problem with the polar coordinate plug-in in PSP, but that invariably reduces the resolution in the textures. At least, it does for me....

...John...

[selden]

Have you tried the "Spherical Mapping Corrector" Photoshop plugin by Richard Rosenman?

"Spherical Mapping Corrector" can be found at http://www.richardrosenman.com/software/downloads/ It

[t00fri]

Have you tried the "Spherical Mapping Corrector" Photoshop plugin by Richard Rosenman?

"Spherical Mapping Corrector" can be found at http://www.richardrosenman.com/software/downloads/ It

Selden,

did you experiment with Roseman's code personally?? I was VERY disappointed by this code, but it may have been an earlier version!

Bye Fridger

[selden]

Fridger,

No, I haven't used his code at all, which is why I posed my suggestion as a question.

I am not a planetary surface texture creator except in one very specialized case -- and that was just a matter of trimming some lines. The other surface textures on my Web site are all just mechanical translations of previously existing maps into formats that older versions of Celestia could use -- which won't be necessary for v1.5.0 and later.

[Dollan]

Thanks, Selden!

I have to run to work, but I'll give it a try this evening and let you, and Fridger, know what it's like.

In the meantime, Fridger, if you have the time, could you tell me what was dissapointing about it? It would give me something to keep a definite eye out for.

...John...

[t00fri]

Thanks, Selden!

I have to run to work, but I'll give it a try this evening and let you, and Fridger, know what it's like.

In the meantime, Fridger, if you have the time, could you tell me what was dissapointing about it? It would give me something to keep a definite eye out for.

...John...

I forgot the details. It was about 2 years ago. I only remember that I deleted everything reminding me of this plugin. It must have been related to the resulting bad quality. But I do have high standards. Perhaps you'll like it, who knows.

Bye Fridger

[Dollan]

It depends on the amount of quality loss, I suppose. My computer system is rather limited, so I can't support the very high quality graphics that you routinely work with. However, that doesn't mean I'll be immune to it. If I'm using a lower resolution than you, to begin with, odds are then that any undesirable results that YOU experience will probably be enhanced more so for me.

When I use the polar coordinate method with PSP, for instance, the end result produces some noticeable pixilation, which is why I've given up on it. This new plug-in I'll have to try, and we'll see.

Thanks, Fridger....

...John...

[Dollan]

Well, I tried it out....

It isn't bad, but I would not use it unless you are working on a fictional world, and one that doesn't have much detail to show anyway. It does indeed relieve the polar pinch problem, but the rest of the map is also distorted, so much so that if you are creating a fictional world with a definite surface geography in mind, it will be completely warped.

My recomendation: use it for the more obscure, cratered or desert worlds. If you are going to make, say, an Earth-like world, it changes everything too much. So this is a useful tool, but not all encompassing. I'm going to need other solutions.

Thus I'll be going back to Google and other search methods, but in the meantime, anyone have any other suggestions?

Selden, thanks for the tip, however. This plug-in WILL be useful, regardless.

...John...

[selden]

Here's another possibility. Like the plugin, how well it works will depend on exactly how you're creating the original image -- what its proportions are, I mean.

The MMPS package provides commands to map from one flat projection to another. The Mollewide -to- simple cylindrical conversion cuts an oval out of the center of an image and stretches the top and bottom of that oval horizontally.

This is not a plugin, though. You have to export the image to ppm format, run the MMPS utility "project" and then convert the resulting ppm image to png or jpg or a format appropriate for converting to dds in another step.

I used MMPS for the images in the document at
http://www.lepp.cornell.edu/~seb/celestia/textures.html
which includes a link for obtaining the package.

p.s.
Staring at the images on that Web page, it seems to me that in some ways it might be more convenient to use a form of gnomonic projection when creating the texture. That would reduce the distortions while the map is being created since you're painting the equatorial part of the sphere and the polar regions separately. However, it would introduce more seams that would have to be taken care of.

[t00fri]

Here's another possibility. Like the plugin, how well it works will depend on exactly how you're creating the original image -- what its proportions are, I mean.

The MMPS package provides commands to map from one flat projection to another. The Mollewide -to- simple cylindrical conversion cuts an oval out of the center of an image and stretches the top and bottom of that oval horizontally.

This is not a plugin, though. You have to export the image to ppm format, run the MMPS utility "project" and then convert the resulting ppm image to png or jpg or a format appropriate for converting to dds in another step.

I used MMPS for the images in the document at
http://www.lepp.cornell.edu/~seb/celestia/textures.html
which includes a link for obtaining the package.

p.s.
Staring at the images on that Web page, it seems to me that in some ways it might be more convenient to use a form of gnomonic projection when creating the texture. That would reduce the distortions while the map is being created since you're painting the equatorial part of the sphere and the polar regions separately. However, it would introduce more seams that would have to be taken care of.

Of course I use the mmps code when I really have do reproject images including pole regions. But that's really more complex to work with.

Bye Fridger

[devil_121]

I'm texturing a simple toy top and I have the modeling and animation down. I'm using a blinn with a ramp for the shader and have a nice shiny red color at the bottom along with a white stripe along the center and a blue color at top. When it rotates you can't really tell how fast it's spinning so I thought I'd mess with putting some crossed lines across the top so you can see them rotate (rotating on the Y). So looking at the top from the top view, I want to lay some stripes over it. Should I try just projecting curves on the surface and do a separate trim surface and color them that way? I think I'm on the wrong track or messed up the layered textures someplace ... ?

[selden]

This really isn't an appropriate forum for generic 3D modelling questions: Celestia doesn't support procedural object descriptions.

How you draw the lines really depends on how the texture is mapped onto the object. If it uses a conventional simple cylindrical projection, vertical lines drawn on the surface texture image might be appropriate.