12 Uploads of the same texture later ...

So I have this 2048 x 1024 source image that I have been trying to split into 2 halves and upload..

Turns out .. no matter how I crop the original source image and no matter how carefully I match up the seams in the tga texture before upload, SL creates a pixel wide border for me .. just enough to where the 2 textures do not match perfectly.

I even checked the uploaded tga's and compared them to the ones uploaded.. and they are different ..! The compressed (1024SQ) version of the same image is perfectly seamless (?)



these textures are supposed to be for resale and I am hesitant because the Horizontal has to be se at 0.998 for them to be "seamless"

In another thread I questioned if PS or Gimp distorts the image on crop..but I am now suspecting that SL is the culprit..

any ideas?

The bordering happens because SL tries to tile all textures. It doesn't clamp them, ever, unfortunately.

Along the right edge, you get pixels blended from the left edge. Along the top, you get pixels blended from the bottom. And vice versa on both.

To solve your particular problem, I'd suggest you simply shrink your 2048x1024 down to 1024x512, and call it a day. There's almost never any reason a texture needs to be that big.

If, however, you've got something like very fine text on there, which would become illegible if it were smaller, or anything equally size dependent (which I'll repeat is EXTREMELY rare), then, and only then, would you want to keep it at full size. In a case like that, the way to eliminate the seam is to overlap your slices a bit. Instead of cutting the texture into just two parts, cut it instead into three overlapping parts (0-1024, 512-1536, and 1024-104 and then use the in-world repeat & offset settings to show just half of each texture on each prim. Align it all properly, and you should have no seam at all.

The downside is you waste an enormous amount of texture memory. Three 1024x1024's constitutes a whopping 12 or 16 megabytes of memory (depending whether or not there's an alpha channel), and in this configuration, half of that is tied up in pixels that are never drawn. Therefore, you should only ever do something like this if there's absolutely, positively, no other way to proceed. In 99.99999% of cases, just make the texture smaller, and you'll win in at least five different ways (lower prim count, less texture memory, less assets, less upload cost, and less work). But if you really, really, really need that big of a texture (which I'll stress one more time, is so rare you could count on one hand the amount of times you'd ever need to do it in your entire life time), this is the way to make it work.

I agree with Chosen that usully, 1024 x 1024 textures are not necessary. But there are some cases, like when I made a football field, where the 1024 x 1024 slices needed to have lots of detail for the field's gridiron and conference markings.

If you are getting a 1 pixel or so lighter edge around the rim, and it doesn't correspond to what is on the opposite edge of that 1024 x 1024 area, you may have fallen victim to Photoshop attempting to anti-alias the edge of your cut to the non-existant material beyond the cut, when you sliced it up. I've run into this before with Photoshop, when trying to slice up a larger image to make seamless .raw files for a multi-sim project.

Try this:

Make copies of each of the 1024 x 1024 slices of your image, as seperate files, and set guide lines right at the edges.

Then expand the canvas by 6 pixels, to make an empty 3-pixel wide border around all of it.

Duplicate the layer with your image, and scale the lower of the two to fit the resized canvas. This will "bleed" three pixels worth of your image's edge beyond the edges of the top copy.

Merge visible, select to the guide lines, and crop.

The end result should be that any partially transparent glitches at the edges, caused by the cutting to slice up the image, will be eliminated.

===============

Note that even if your sliced image is 100% PERFECT, SL will still take a 1x repeat pattern and try to bleed opposite edges to each other. So for example, where one edge of my football field texture is clean gras, and the other edge is a white marking line, the grassy edge is going to have a 1-pixel white smear along that edge opposite the edge that really is white. The only cure for that is to use a 0.98 repeat on the prim.

Ceera, I'm sure your football field is beautiful, because I know that you know what you're doing. But if you don't mind my offering an alternative methodology, I probably would have taken a different approach.

If I were to make a football field, I'd most likely do it in two layers of prims. The base would be a repeating grass texture. Just above that, I'd put the (slightly translucent) white lines and numbers on otherwise transparent prims. That way, with just a handful of small line textures (straight line, L-corner, T-corner, etc.), a number sheet, and one detailed grass texture, I could do the entire field, with very minimal texture memory requirements. The processing overhead would be slightly higher, since there'd be transparency involved, but in the end, I think the memory savings would win out. I'd probably only do it your way if I were extremely strapped for prims.

I don't mean to say your method is in any way wrong. I'm just presenting an alternative.

I considered that. But the resulting alpha-sort glitches for every alpha-textured item placed anywhere near that surface were simply unacceptable. I tend to wear a furry avatar most of the time, so my tail and often my legs, not to mention skirts and hair, will usually show glaring problems in places where a transparent overlay is used like that on a "floor" surface.

My field, incidentally, was eight 1024 x 1024's, each tiled over a 3 x 3 array of 10 x 10 x 0.5 prims, and surrounded by a seamless plain grass texture that was likewise tiled as a 0.333 repeat on a 30 M wide strip of prims around the gridiron. It can be seen in the RUCE 3 sim, if anyone is interested. It's the Rutgers University sandbox sim.

Bear in mind though, that the rest of that sim is pretty simple. The entire football stadium is only about 1000 prims, for a full-scale stadium, and there is very little else in the sim, other than some trees and streets. So I could afford a handful of high-rez textures, so the client's environment would look its absolute best.

Good points, all, Ceera. I figured you probably had good reasons for going that route. You usually seem to have good reasons for just about everything you do.

Thanks you 2 ...

I guess as long as the person using this texture understands that this kind of thing is not a "product defect" I am ok with telling them to use a lower repeat. Afterall you cannot tile 2 textures on the same prim surface so some customizing is usually in order anyway when installing these on a project.

as I said.. I even manually took the opposing edge columns of Pixels and manually installed them on the tga just before upload.. to eliminate any chance that there was some anti-aliasing from Photoshop. ( I did not see a visible problem but still did it anyway to make 100% sure) I even overlapped columns once to see if that would help.

FYI Gimp also cut the picture perfectly without added steps

As to the resolution of the texture, this is a super detailed Antique Hardwood floor with minute cracks between the horizontal planks that I designed to cover very large areas, and when you reduce the resolution, these dark crack lines start to strobe like crazy in world. Some things are worth the extra load on the system.. and in my view, this would be one. This is not one of those textures that you would put into a cheap multi pack just to increase the quantity count of the textures in the pack like so many textures out there. Were this the case I wouldn't have made it by hand and I would definetly have made it a 512 and be done with it.

Btw... maybe one day when I run out of ideas for stuff.. I will take something .. hue rotate it 10 different ways and sell it as a 10 - pack ..as seems to be the trend with most other people selling textures.

Some low-end 10-packs of textures from smaller stores do work that way, but the better texture bundles don't. Better texture artists will, at least, have the details and shading on one layer set, and the color/fabric texture/tint base on another set. That way, when changing a set of bricks from red to yellow to grey, they can ensure that the mortar, shading and highlights don't change with the color shifts. This is also what most clothing designers do when offering a dress or other outfit in several different fabrics or colors. This allows you to get the same look, but change color scheme. Or to offer something like upholstery textures for furniture, in different colors of leather with different grain patterns, or in different fabric choices, while keeping the product looking like they all came from the same factory.

Most of the "10-packs" are actually themed sets. Things like the inside and outside of 5 different window styles, all in a matching type of wood trim or in the same painted color, so a builder can have some variety in window styles, while not making it look like each window was painted by a different day-laborer, with whatever paint or stain that laborer could scrounge up.