NormalMap problem

[Cham]

I'm experiencing a frustrating problem with my Moon textures, and I don't know how to solve it. I'm using few base textures of the moon, in various format (jpg, png and dds), in 2k and 4k resolution. Those textures don't have any edge problem and they are looking totally smooth if I use them without any bumps or NormalMap.

I also have a nice NormalMap in JPEG format and 4k resolution. Apparently, there's no edge problem on it, as seen in Photoshop. But then, I always end with this line on the Moon (horizontal line below), when I use the NormalMap with any base texture (whatever the format or the resolution). This line coincide with the joining edge of the texture, which is folded on a cylinder, but I can't remove it even if I blurr dramatically that part of the textures (base or the NormalMap itself). Why ?

[t00fri]

Cham,

that sort of line (at the joining position) is a quite common "little problem" in texture making. Just rotate your texture horizontally by 180 degrees (wrapping mode), such that you see the joining line manifestly in the center of your image after loading it into PS or Gimp. Then use one of the standard "repair"/smearing tools that allow to copy some smoothed nearby strip of the same texture onto the line. After some practicing, it's really easy to make it vanish completely this way. Then, finally rotate the texture back.

Good luck,
Bye Fridger

[Cham]

I don't understand. That NormalMap appears to be fine, after rotating it by 180 degrees (offset in PhotoShop). I can't see any line at all in the middle of the texture, in PS. I also tried to blurr that part and also used the stamp tool, and that annoying line is still there in Celestia. Like I said, I can't see any line in PS, even after having made the offset (with wrapping edge).

[t00fri]

I don't understand. That NormalMap appears to be fine, after rotating it by 180 degrees (offset in PhotoShop). I can't see any line at all in the middle of the texture, in PS. I also tried to blurr that part and also used the stamp tool, and that annoying line is still there in Celestia. Like I said, I can't see any line in PS, even after having made the offset (with wrapping edge).

How about the base texture. That's what I was thinking about. Rotate it by 180 degrees and have a look and magnify so much that you can distinguish individual pixels. Also the patterns on that base texture are discontinuous.

Bye Fridger

[Cham]

Of course, I also checked the base texture, and made an offset in PS to look at the edge. I don't see anything special there, the texture looks like very smooth. I also made a blurr on the edge, just in case, and no luck. The line is still there in Celestia. Anyway, I also checked that texture without using the NormaMap, in Celestia, and there's no line visible. This line appears only when I activate the NormalMap. I'll have to do more experimentations on both textures (base and NormalMap).

[selden]

Cham,

What kind of model are you using your textures on?

One of Celestia's default spheres or one that you or someone else made?

The placement of a texture onto a model is controlled by texture coordinates within the model itself. If those coordinates are slightly displaced near a seam in the model so that they're slightly to the inside of the edge of the texture, it could cause the effect that you see.

[Cham]

Selden,

I'm using the texture on the standard Moon only. So it's just a simple sphere.

I just tried the NormalMap without the base texture, few minutes ago. The Moon is then white with bumps. The line is still there, so this test proves it's the NormalMap alone which has a problem. If I activate the base texture and desactivate the NormalMap, there's no line visible.

But then, if I blurr the NormalMap, I still have this line. That's the source of my problem.

[selden]

Cham,

This does suggest that Celestia may be applying the texture incorrectly.

Can you add some fiducial marks at the edges of the texture? I mean add some marks that would help determine just how much is being trimmed.

[t00fri]

Did you really zoom the normal map up to the level of seeing individual pixels??

Bye Fridger

[Cham]

Did you really zoom the normal map up to the level of seeing individual pixels??

Bye Fridger

Of course ! I zoom until I see clear pixels.

I'm puzzled by this, as I can't see any clear line in PS, whatever the zoom factor.

[chris]

Does it have to do with texture splitting? If you have a 4k texture but your hardware only supports 2k, Celestia will have to split it into 2k chunks. Since hardware can't filter across texture boundaries, you might see a line there, though I'm suprised that it's as pronounced as it is in your screen shot.

--Chris

[Cham]

Chris,

I don't think my problem is related to that. My video card (ATI X850 XT with 256 MB) is certainly capable to show 4k textures. At least, I don't have a line problem on other planets or moons, with similar 4k NormalMaps and/or base textures.

I'm pretty sure my problem is caused by a "buggy" Moon NormalMap. I just can't see that line in PhotoShop, and whatever I do to this NormalMap (blurr, Clone, etc), the line is still there in Celestia.

[Fightspit]

Your graphic card (ATI X850) doesn't surport the "4k" texture.
See here:
http://www.ati.com/products/radeonx850/specs.html
In fact, nothing is writen that your graphic card support the "4k" texture.
So, the ATI X850 supports a maximum of "2k" texture.

All X1xxx series support it:
http://www.ati.com/products/RadeonX1950/specs.html
http://www.ati.com/products/RadeonX1900/specs.html
http://www.ati.com/products/RadeonX1800/specs.html
http://www.ati.com/products/RadeonX1650/specs.html
http://www.ati.com/products/RadeonX1600/specs.html
http://www.ati.com/products/RadeonX1300/specs.html

High resolution texture support (up to 4k x 4k)

[Cham]

Huh !!??

But then, how can I use 4k textures (4096 X 2048 with spec maps, bumps, etc) in my large addon "Zeta Reticuli" ? Most object are using 4k textures in that addon, and even many moons are showing at the same time with their 4k textures ! This brings down my video card to its knees, but it works nicely anyway. So I'm sure my viideo card does support 4k textures !

[Fightspit]

Sorry, it is 4kx4k (4096x4096) not "4k" (4096x2048).

[t00fri]

Cham tell me the url for your normal map or send it. Unlike your ATI card, my NVIDIA card does support 4k textures. Your ATI card will split the 4k into 2k chunks whence a border line may result. Just as Chris explained.

If I don't see your line, Chris was right

Bye Fridger

[chris]

Huh !!??

But then, how can I use 4k textures (4096 X 2048 with spec maps, bumps, etc) in my large addon "Zeta Reticuli" ? Most object are using 4k textures in that addon, and even many moons are showing at the same time with their 4k textures ! This brings down my video card to its knees, but it works nicely anyway. So I'm sure my viideo card does support 4k textures !

Celestia works around the hardware limits by splitting the textures into chunks that hardware can handle. So an 8k x 4k texture would be split into 16 2k x 1k chunks on your card, or 4 4k x 2k chunks on a GeForce or Radeon X1xxx.

Note that texture splitting does not work for mesh objects.

--Chris

[selden]

Cham,

One of the items listed near the top of Celestia's menu Help/OpenGL Info should be the maximum size of texture that your card can handle.

[Cham]

Cham tell me the url for your normal map or send it. Unlike your ATI card, my NVIDIA card does support 4k textures. Your ATI card will split the 4k into 2k chunks whence a border line may result. Just as Chris explained.

If I don't see your line, Chris was right

Bye Fridger

I got it from the Motherlode, here :

http://www.celestiamotherlode.net/catal ... don_id=611

If there's a better 4k NormalMap of the Moon, I need it !

[t00fri]

Cham tell me the url for your normal map or send it. Unlike your ATI card, my NVIDIA card does support 4k textures. Your ATI card will split the 4k into 2k chunks whence a border line may result. Just as Chris explained.

If I don't see your line, Chris was right

Bye Fridger

I got it from the Motherlode, here :

http://www.celestiamotherlode.net/catal ... don_id=611

If there's a better 4k NormalMap of the Moon, I need it !

With all scrutinity, I cannot find your line. So I suppose it's your ATI card not being able to deal directly with 4k.

Bye Fridger