Ugly Neighboring builds and occlusion culling

My sister just had one of those ugly prefab stall malls move in next door, and wanted to build a nice invisprim wall to block out the sight...

except that the invisiprim textures (beatfox's old post) no longer seem to do occlusion culling. (translation: invisiprim textures don't count as alpha'd textures, so should block everything behind them except land IIRC)

when did this change? is there a way around it w/o doing some kind of custom landscape texture on the near side of the wall? is there possibly a different UUID that someone has that WILL do occlusion culling, but still render transparent to show land?

any help is appreciated

I did some tests with a wall of invisprims and everything behind it was being occluded, although not perfectly. Objects and terrain at times flicker in and out depending where you're standing. The closer you were to the invisiprim, the more it would occlude geometry behind it. The farther away, more objects become visible but flicker visible to invisible quite often.

I also tested to see whether or not the occlusion culling was the same or different between a wall of non-alpha'ed prims and a wall of invisiprims using the Debug menu (CTRL-SHIFT-ALT-D). Under Client> Rendering> Info Displays> Occlusion, both walls occluded the same way. You can see what polygons/triangles are being rendered (and what isn't) at that very moment by the wireframes that show through solid objects. This debug feature should not be confused with Wireframe mode (CTRL-SHIFT-R).

Void, the occlusion culling is functioning (even with invisiprims), although it's not functioning the way you want it to. I believe its the same as from a year ago. I remember making a mega-invisiprim wall back then with the same script and the occlusion culling operated in the same fashion.

weird, I'll pass it along. according to my sis it wasn't occluding at ALL at any distance for any non-alpha'd things (and I trust she knows, she's smarter than I).

could it possibly be a client issue? she uses the nicolaz client, (as do I).

I'm not familiar with (or aware of) any SL clients outside of the ones supplied by the SL website, so I wouldn't be able to answer that.

You could try downloading and installing the current SL client listed on the Second Life website and do a comparison test.

I've never seen invisiprims serve to hide anything that's not 32-bit textured. That's pretty much been the whole point of them all along. They hide avatars because avatars always have alpha on them. They don't hide most other things because most other objects have 24-bit texturing.

Occlusion culling or no occlusion culling, that behavior has always held true for me.

Chosen, if you make it big enough, or zoom in close enough, it will. Invisiprims act the same way as solid, non-alpha textured objects when it comes to occlusion culling. The difference being, with invisiprims, you can see through what is not there (paradox?).

The object's occlusion abilities is only proportionate to the objects behind it. If any part of a prim's geometry is visible, or near the edge of visibility, from behind a foreground object, it gets rendered and not culled by the client viewer (keep in mind this is from your client's camera point of view). But if an object is fully blotted out by the foreground object, and not near it's edge, then it would be culled by the client and not rendered (the Info Display> Occlusion option in your Client debug menu visually demonstrates this).

That's why invisiprims used on avatars doesn't make everything behind it disappear. The client calculates it isn't large enough in the viewer to warrant applying occlusion culling... until you zoom in very close. At which point, you'll begin to see objects behind it flicker and disappear as well as the terrain (but not the horizon, strangely enough).

I'll put up some screenshots so you can see (or not see) what I mean.

Well, I'll be. I had no idea. You really have to zoom in tight on it, but it works. Very interesting.

Of course, it makes perfect logical sense that it WOULD work. I just never thought about it before. And since you have to get so eyeball-bleeding close to notice the effect at all, it's not something I would have just stumbled across.

Interestingly, it seems to cull not just prims but land as well. I thought land was exempted from occlusion culling. I guess not.

I get to be wrong about two things at once on this one. Woohoo!

Here are the screenshots -

Lovely floating signs and other monstrosities:


The same thing but w/ Occlusion debugging:


Invisiprim script on 3 megaprims:


Invisi-mega-prim w/ Occlusion debugging


Even though the Invisiprim screenshot doesn't show it, some objects briefly flickered visible. I'm not too sure what the wireframes in the Invisiprim Occlusion screenshot are from. I believe they're sim boundaries but I'm not completely sure.

Oh, btw, I found the option to turn on and off Occlusion Culling. It's under Client> Rendering> Object-Object Occlusion. Or you can just press CTRL-SHIFT-O.

Void, you might wanna give it a try, or have your sister do that and see what happens.

Chosen, I held that same belief until I decided (out of sheer boredom) to mess around and test invisiprims about a year ago. Sometimes you just gotta keep an open mind to find unexpected answers.