From 28 prims to 1! My method

I'm sure this has been done before but I've found a great way to save prim count while making a pavillion/consevatory. It is made from wall/window panels with arched glossy brass window frames. Such a panel is 14 prims. Clearly if the building is giong to have 10 or more of these panels it is a lot of prims.

So, to maintain the original look I snapshotted the panel face-on, having made the window glass blank/opaque/white, and then in Paint! I copied and pasted just the panel to get rid of the surroundings. Next I went into photoshop to turn it into a TGA with transparent glass, and uploaded. I applied the texture to both sides of a flat panel - presto - 1 prim doing the job of 14. Better still, I doubled the width of the panel and sized the texture so it fitted twice, side by side. Now 1 prim was doing the job of 28! Set the texture to full-bright and it looks as good as the original. Woot!

This should be a feature of the build tool.

Select a bunch of prims, and one click converts it into a texture pasted onto one prim

Yeah! I'm a total prim cheapskate so anytime I've got a wall with any openings I just do a texture for it that takes care of the wall, framing, glazing, etc. all in one shot. It doesn't look as good as a multi-prim wall, but it saves me lots of prims.

EDIT: I just re-read your post and it's even more brilliant, if I understand correctly. You built the multi-prim version, took a screen shot and then made that the texture? Clever, since you'd have some appropriate in-world shadowing, etc.

Just a quick word of caution if you're going to be using this method. The larger your build, the less reliable the technique will be. Because SL has no orthographic cameras, only a perspective camera, there's always some amount of perspective distortion in your snapshots. Things toward the edges of the screen will appear proportionally smaller than things in the middle of the screen. The effect is amplified as you zoom out.

For small to moderate sized items, you can get away with using the raw screenshot as a texture if you're careful about your camera placement. For large items that require you to zoom out to see the whole thing, like for example a building facade, you're going to have to do some perspective correction in Photoshop in order for it to work well.

Another caution on this method. Using whole walls that are a 32-bit TGA texture, and placing them side by side, you have a very good chance of having problems with the "Alpha Sort Glitch" - which means that whe you look at corners made this way, or for that matter ANY line of sight that has two 32-bit textures in that line of sight, there is a good chance that the faces of the prims will render in the wrong order. This means you'll see part of the interior wall through the exterior wall, or have other strange artifacts.

That said, yes, used carefully and in the right places, that method can do tremendous things for reducing prim counts in SL building work.

Is it possible to attach a big object to a HUD, and take a snapshot of it? That would fix the perspective problem.

The original must have looked pretty bad for this technique to have made it look as good as the original.

Whether the original looked good or bad is not the point. The point is full birght eliminates any additional shading on the new surface that wasn't captured by the snapshot from the original. But you knew that already. Never a missed opportunity for an insult with you, is there?

I guess you could take several snapshots and stitch them together. There are plugins and standalone tools that do this. Autostitch works pretty well for me.

I've done this a few times to rebuild freebies to have fewer prims. On the gazebo on my land I shaved off over 200 prims this way, from 300 to 100! There were lots of slats being used for these cross-hatched sides; I took a screenshot, replaced the multi-prim patchworks with a single flat and applied the screenshot to the texture.

I think my original panel was 5m x 5m so there was no problem with perspective. I turned the glass white/opaque so it made the selection wand more accurate in Photoshop.

Next Photoshop texture-playtime for me might be to do nice realistic decorated sides for my British-style canal narrowboat.

if you turn your render distance WAY up. then back away( about half a sims worth) then "Ctrl+" (thats 2 buttons to zoom) several times to zoom way in... well it's still not ortho, but it comes a lot closer than regular.

yes it works quite well (long as you scale everything down tiny)