Help! "Splicing" textures across prims!

I'm confused, I already did this once and it worked flawlessly. I took a 1024 x 512 image in PS and split it right down the middle. I uploaded both 512 x 512 images, applied them to adjacent 10m2 flat (.05) prims and voila, a 10x20m wall mural. It was seamless from every angle and looked fantastic. This was in a sky box that has since been taken down.

Today, I took the SAME EXACT two textures and applied them to adjacent 10m2 flat (.05) prims and now I have a glaringly obvious black seam down the middle.

When I zoom all the way in on the seam, it appears that there is some type of very small gradient shadowing effect taking place at the outside edge of both textures.

The allignment of the prims is perfect, and the textures are aligned to 1 verticle, 1 horizontal per face with no offset, jsut as they were when I did it the first time.

THis has actually happened with two different sets of wall murals, one is 10x20 and one 10x30, both of which worked before.

Local lighting is off, shadows are off and there are no local light emitting prims that I am aware of.

What am I missing?

It's probably the other side of the texture wrapping 'round to the other side. This happens, I'm told, so that prims with the same texture on next to each other don't have a seam between them. No idea why it didn't happen for you before.

Two ways to solve it, the easiest is to set the repeats to 0.99 or similar - this is the standard way to get rid of the wrapping. The best way to do it, however, would be to upload the image as one texture and align it so that half is on each prim as this will load more quickly than two textures.

There's no need to slice the image in Photoshop. SL has its own tools for governing what portion of a texture display on each prim. In the editor window, click the More button, and then go to the texture tab. You'll see a bunch of numerical settings for repeats per face and offsets. Heres what to do:

1. Upload your texture as one single image.

2. Set the repeats per face on both prims to .5 on the horizontal and 1.0 on the vertical. This will cause each prim to show 1/2 the texture. (I'm assuming here that your 10x20 wall is 10 high and 20 wide. If it's the other way around, use .5 vertical and 1.0 horizontal.)

3. Set the offsets to .25 horizontal on the right hand prim, and -.25 on the left one, and keep the vertical offsetts at 0.000. This will move the texture from being centered on each prim to being spread evenly across the two from left to right. (Again, if you're going the tall way instead of the wide way just flip the numbers so you're affecting the vertical positioning, and not the horizontal.)

That's all there is to it. This technique will work whether you want to spread a texture across 2 prims or 200. Just do the math to determine what portion of the texture should be displayed on each prim, and plug in the numbers. This is much more reliable than pre-cutting in Photoshop, much less resource intensive, completely non-destructive, and a hell of a lot cheaper.

I will test these ideas later tonight and post which one spefically works best, though I suspect both will.

Thank you so much again,
Erik

I can tell you now; the one using one texture will.

I would just add to what Chosen said that if you activate the "Select texture" mode in the edit window, and select a prim face, you'll get a grid that will show you the texture's edges and center (with a circle). That makes it's easier to figure out the repeats and offsets.

It actually appears there is now one reason for slicing textures in SL.

If you want to 'map write' e.g. a sign on your roof saying, e.g. "I <3 SL" you can try to get a small number of textures and use texture scaling and offsets to make it look nice and large so the mapping agent spots it.

Actually what happens (assuming you're using black text) is you get a grey smear. It appears the 'bot that does the mapping looks at each prim, and more specifically the texture on it but doesn't get the scaling and offset information properly. For I <3 SL of course you can build the shapes with prims easily enough, but for other textures it seems likely you'd be better slicing textures. I haven't actually tested the sliced texture approach, prim writing worked just fine but sometime I'll do the slicing too and report back.

That said, as Chosen et al. have already said, for every other application in SL unsliced textures and the existing resizing tools are the way to go.