Sculpted Prims: is there anything they cannot do?

I'm posting this is Resident Answers because it involves the issues/limits of a feature rather than how do use it. Mods, if you feel this is an error please move it

I am convinced that sculpts HAVE NO LIMIT. So many times I've thought I have learned every technique, only to learn more. I've given up on thinking that I am anywhere near a level of sculpt mastry... it could take a year of intense experimentation just to discover all the things they can do, all the possible uses, and how to use them with complete efficiency, to say nothing about actually making finished objects with them.

However, I may very well be wrong. If anyone can think of something sculpts cannot do, please post it! For now, I will post proposed problems with sculpts, and how they can be overcome. Many of the demonstrations are visually uninteresting, but technically intriguing.

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1) Sculpties may be good for organic things, but useless for geometric things.

Completely sharp edges are possible to the point of making stuff indentical to prims. Moreover, sculpted sharp-edged geometrics can look _better_ than prims.

Comparison of same stair shape. Left is sculpt, right is made with cube prims: http://img129.imageshack.us/img129/1009/sculptdemostaircomparedv3.jpg

Sharp octagonal sculpts, plywooded for reference: http://img515.imageshack.us/img515/3749/sculptdemosharpshd2.jpg

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2) Sculpted prims may be polygon efficient, but they are polygon wasteful. This is especially so because sculpt meshes are 32x32, without irregular sizes such as 8x128 for a skewed amount of axis detail.

By folding up polygons like origami, one can bypass the conventional mesh size and get an absurd amount of efficiency. Here is a picture of the most efficient object ever created in SL. 56 steps, completely sharp (textured with plywood, no faked lighting) and geometrically perfect. It does the job of 56 prims with just two: one sculpt, one collision prim. It does this with half the vertices of those prims.

http://img255.imageshack.us/img255/9989/sculptdemo56stepxc4.jpg

The 56-step object pretty much exhausts every vertex. Also, it is so large its use is mainly outdoors. Cut the step count in half and you get something perfect for interiors, has a more useful shape, and has sides which texture completely perfectly (and is incredibly easy to make custom textures for.) As you can see, even though it is folded like origami, it shows no trace of being so, and appears completely solid.

http://img255.imageshack.us/img255/724/sculptdemo28stepsaj6.jpg

Other things that could use this: anything that requires lots of detail on two axis and limited on a third. Stuff like bannisters, fences, etc, can be made with an arbitrary amount of posts; around 30 per prim. Gears with 24 sharp teeth. Bent and extruded cubic shapes with 30 turns. All of these are just with using sharp edged techniques, which take up a lot of vertex overhead. For smooth objects, double the efficiency.

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1) The spherical collisions of prims make them useless for cars and vehicles.

By maximizing the range of color values, one can make the collision sphere match the shape as closely as possible. Then one can either create clear prim bounding boxes to throw out messy collision, or in the case of cars, simply use a front "plow prim" (already often used for land vehicles) and conventional prim wheels to raise the spherical collisions off of the ground.

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2) The spherical collisions of sculpts make them useless for architecture.

There are two types of architectural things: stuff you bump into, and stuff you walk upon. The former includes wall details, doors, windows, columns, and other elements. For these, the collision spheres are close enough to be used as-is. For stuff that you walk upon or may walk upon such as stairs and roofs, the sculpt can be set to phantom, with secondary cubic prims set to a transparent texture sized and adjusted to fit the shape, giving perfect collisions.

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3) Sculpts cannot create multiple disconnected objects on the same prim.

This may seem like a silly issue to raise, but when you think of something, it is best to think of what you _want_ them to do, whether or not it seems possible. This is something that is indeed possible: here is a proof of concept using simple cubes. There is no alpha face faking; it is textured completely with plywood. Virtually any object could have multiple disconnected copies of itself on the same prim.

http://img266.imageshack.us/img266/4172/sculptdemoimpossiblelc2.jpg

Your prim-fu is strong!

One thing I thought of in terms of the collision issues is just making invisiprims that take the basic shape of the area you want to collide with things...like with a vehicle since you're drastically reducing the amount of prims involved you would easily be able to add an invisible sphere or two or whatever to give it the same basic phyisical shape of the sculptie. The same would be true for architecture.

I'm doing the same thing with this av I'm working on. It's a robot that turns into a vehicle and flies like one. Since the av doesn't collide when sitting on anything but the whole vehicle is essentially the avatar I just made a couple invisible spheres positioned so the wings and front and all that would appear to collide with the ground or other objects.

I've been getting really tempted to sit down and figure out one of these free programs and start trying to transition toward sculpties. The more I look at the info the easier it seems it might be!!

I just need a whole weekend with nothing else to do...a rare commodity for me these days!

I was so disappointed by the LoD problems that I quit working with sculpties and then got busy with other stuff, so never got around to testing this: Don't the new sculpt types (e.g., PRIM_SCULPT_TYPE_PLANE) make the collision envelope more workable?

Oh rite how could I forget LoD problems!
Those too can be addressed. I'll even describe exactly how to do it very easily. Open up any sculpt in photoshop, and press control M to bring up the color curves tool. This scales all the color values to make the mesh smaller even if the SL object size is the same. The magic numbers for this are 0->95 and 255->159. Anything else symmetric also works, but these are the best. This is exactly perfect to match LOD with object size; the LoD won't change until you zoom out far enough that the object is so small LoD reduction is irrelevant. However, it isn't so small that you will be rendering polys unnecessarily from higher distances.

If you just use color curves on one color value instead of all, you can scale the mesh however you wish. This is especially useful for megaprim sculpts, which have a set size; you can make something 20x20x20 meters by scaling the Z axis (blue channel) of a sculpt by 0->85 and 255->170 and applying it to the 20x20x60 megaprim. So using this, you can not only make the very small (jewelry, anyone?) but also the very large.

Here is a visual example: both of these objects are 2x2x2 meters. Because LOD is proportional to SL object size and not mesh size, they have the same LOD falloff.

http://img255.imageshack.us/img255/6370/sculptdemolodpt4.jpg

Who is using scultpies in SL? I can't seem to find any major scupltie works in-world. Before they were released everybody was saying how great they are, but now I don't see them being used very much.

I've seen a few things already. My buddy has a civil war hat that's a sculptie from a pretty popular clothing place.

Based on how much is involved in making sculpties I suspect we'll see them slowly transition into the market as opposed to just popping up one day.

Sculptie prims are reaaaaaally cool =oP Everytime you think you've seen it all, someone ups the ante.

However, I've always been confused why Second Life bases it's "bandwidth economy" on the prim, especially as we stuff more and more complexity into a single prim. The prim is probably really the only practical way to "measure" and carve up everyone's share of the pie. But I don't think there is near as much impact with lag going from 100 prims to 1000 prims, as factoring in things like texture resolutions, physics, AI (I'm used to games with NPC AIs, does a world of all residents and no NPCs, even have an AI?), mesh complexity and facets (rather than primitives) , alphas & flexis, scripts, and of course visitors with-or-without all their fancy attire. Some of that however I guess is probably based more on the user's graphics card and not bandwidth at all -- maybe the magic of math really DOES stuff all of that info in one little prim, and the problem is people's systems are struggling to keep up? Otherwise sculpted prims seems like they will let everyone jam a little bit more into that suitcase that's already about to burst..

Maybe there really is no other way to measure, and if people don't monitor their own parcels they will be the first to suffer. Or may be it's just as well to "force the issue" because the sooner it all teeters towards collapse, the sooner they are going to have to find that magic bullet solution (not sure what that will take). It just seems sculpted prims push the issue that much harder.

Ouch, my head hurts. I hate trying to think.

(*This is the cue for one of you geeks who understand this stuff to explain it maybe again, though probably again most of the explanation will go over my head ...)

They can't bring back my kitty.
He got run over.

I had that explained to me once and from what I understood, the system considers the sculptie to be the shape that actually collides (the half-sphere or whatever it is) and the making of the sculptie's shape is done client side which is why there are the textures to tell the client what it's shaped like.

That's probably not that accurrate but that's the best I've figured it out from what I've been told. Makes sense to me!

i have a few sculptie pieces im not impressed with them as i thougt i would be

they looked great in the pictures so i spent a ton of $L on them put the outfits on and was saddened by them

saw sculptie stairs i almost bought till i found out when walking on them they look weird cant walk directly on them so glad i didnt buy them

they are ok i guess but i spent about 2k on items with sculpty parts in them that left me wishing i hadnt bought them at all or wishing the pictures had shown them from all views and angles so i knew better what i was getting

Well, I barely know what I'm doing but I built a sculptie Stonehenge sort of thingie. Of course, you can't really walk between the stones because of the problems mentioned above. Big rocks are easy so I guess it's not a major sculptie work, just amateur, but I like it. And there's no texture baking going on. It's really going to be my garden.

I would post the coordinates, but I don't know if that's against the guidelines of these forums. I'm not selling anything there though.

I really do wish you could walk between the stones, and I did see a lawn and garden vendor in world with a sculptie stone arch you could walk through, so maybe they used the invisible prim method.

--KC

Post them coordinates! I'd love to see it!

Also, if you made the sculpties phantom and put invisible prims over them they would have the illusion of being solid! I dunno what your prim limit is, but it would be worth the effort imo!

Ok - I don't see anything in the guidelines against it.

KC's Cromlech, Kona Island (221, 151, 21)

Is that enough information? It's not in the classifieds. On the map it's the little patch of gray blobs on the eastern shore of Kona. The neighbors seem to love it.

I have the spare prims to do the phantom technique. I really appreeciate that advice! But it will take me quite a while to get around to it. The skybox above (which anyone is also welcome to poke around in for now) is draining all my building patience! --KC

The big thing sculpties can't do at the moment:

Be built without external software.

I know NOTHING about sculpties, but I heard somewhere that they can't be made flexible... is this true?

Only cubes, prisms and cylinders can be made flexible.

(One of the freebie classes where I didn't fall asleep. I tend to take naps at odd inappropriate times anymore, especially when the teacher can't see me.)

Supposedly, we'll be getting a cylinder based flexi at some point, and that should be able to go flexi. I hope so, I can't wait to make a really nice sculptie-flexi tail =^.^=

Then again, we're also supposed to have a more advanced Havok physics engine, llTeleportAgent, etc etc...

In addition to architecture, sculpties are also useless for landscaping. Caves, natural stone bridges, floating rocks or islands in the sky... collision issue makes it impossible to walk on those things, unless the floor is flat enough to add a regular prim as collision prim (and then I wouldn't need a sculptie anyway).

Also a big issue for me: the polygon reduction when you zoom out (don't know the technical term). Normal prims usually look good enough when viewed from a distance; if a cylinder turns into a hexagonal bar, that I can live with. The length and overall shape stays the same. But sculpted prims often appear shorter, holes appear between conjoint sculpties, curves get pointy, pointed ends get rounded off.

Especially an issue with avatar attachments, since one rarely zooms close enough to see them at 32 x 32 polygons. For example: a short hairstyle done with a sculpt prim, close to the avatar skull. Only looks as intended if you zoom onto the avatar head. View the avi from a distance of 3 or 4 meters, and the hair will already look like crap. Viewed from 10 meters distance, you'll see a severe case of alopecia.

A few of my clocks use them, and some other things I've done, check my profile picks for a teleport to my store to check them out if you want.

I am working on an underwater cave using sculpties. The layout is complete, and yes I had to set some to phantom, but the illusion is great!!

See it here: http://slurl.com/secondlife/Pimushe/32/224/7

I don't seem to have the LOD problems others have, but all my detail sliders are maxed, if that makes a difference.

Yes, they cannot be made flexible.

http://www.rebirthed.com/guildsnapshots/NecklaceShoot3.jpg

I shuffled through my photoshoot for untouched pictures, and they're big and pretty raw (in fact, ignore that one texture fault on the tiara, I fixed it before boxing) but they show the sculptie use very well.

I love my sculpties in jewelry crafting.

Lag + Sculpties is very very very bad

That nice sculpty hat you have is a solid sphere that covers your whole head (sometimes for several minutes). I wouldnt think about doing a big build with them.

Untill you can make them in the viewer they are just a toy for those who like to tinker.