Semi-transparent sculpty: help

I've been trying to make a sculpty mattress in ZBrush. I've been trying to round the corners, bevel the edges, and add a few minor hollows and bumps to the surface. It looked great in ZBrush, but not so great in SL, where my edges look kind of ragged. But my major problem is that once I convert (with 2K's great converter) and import, the object is semi-transparent. I thought I read something about an option I could check in ZBrush to fix this, but I'm not sure. Anyone know? Here's an image FYI. (The poles in the background are my boat; sorry about that.)

Your object inside out. Flip the sculpt map over in any image editor, and the problem will be solved.

As for the "ragged" edges, make sure you upload your map image losslessly, and they'll straighten out (assuming the source model is well made to begin with).

Thanks, Chosen. Those sound like surprisingly easy fixes! And yeah, I did not upload my map image losslessly; I'll give that a try.

While I have your attention: do you know any way to get rid of the "poles" on ZBrush prims like the Sphere3D and Cube3D? I'm half tempted to try building something manually using zSpheres, but knowing me I'd mess up the poly count. Maybe another alternative is to create a prim with so few vertices that ZBrush can't create its poles at all?

You can use SweepProfile3D to create an object without a top and bottom and then apply it to a sculpty cylinder in SL.

If you're using spherical topology, you must have two poles. This is a requirement of sculpties which exists regardless of what modeling program you're using.

Zspheres won't work, as their topology is completely different. Or at least they shouldn't. I've never actually tried it, so I hesitate to say with 100% certainty that it won't work. I am 99.9999% confident it won't work, though.

As 2K said, you can use a cylinder if you want to, but it will have an open top and bottom. If you want it to be a closed surface, poles are necessary.

Your suggestions helped with the mattress quite a bit. I've attached a photo. It still needs some work, and I'll probably want to make a more "fem" version of this bed (I'm thinking comforter with a light texture, rounded headboard), but this is a start.

I'm curious -- does cubical topology also require two poles? There's probably some good geometry reason if so.

I tried zSpheres on a lark, but ZBrush crashed three times in a row as I was modeling with them, and I rarely get crashes in ZBrush. Maybe the zGods are telling me not to bother trying.

To make the comforter, I've come close with two or three different 3D primitives; the deformation pallette can work wonders. Still, the darn meshes are always so funky that I have trouble bending the "sides" of the comforter to point downward. It's those danged poles. Any advice on how to make a U-shaped object like that?

ZBrush always crashes after applying an initial deformation function to a newly created SubTool or ZSphere.

I'm guessing you created your ZSphere object and then went to deform the object and it crashed. To prevent this you can sculpt the surface of your object slightly using something like the Standard brush and then hit 'undo'. You'll then find the deformations work fine.

If you're going to try to convert a ZSphere then I suggest you disable the 'Grp' button in the Export panel. But be warned that ZSpheres initially don't have a UV Map, so texturing the thing may later turn out to be a problem.

There's no such thing as "cubical topology" as far as sculpties are concerned. And yes, there is a good geometric reason. Everything has to be able to unwrap into a perfect rectangle. There's no good way to do that with a six-sided cube. You need shapes that are one-sided, meaning spheres, cylinders (sans endcaps), toruses, and planes. No other primitive shapes are very well possible with just a single contiguous surface.

Of course, those shapes can be deformed into anything you want. But underneath all the modifications, they're still just spheres, cylinders, toruses, or planes.

99.9% of the time, spheres are all you need. A sphere can be deformed into almost any shape you can imagine. Here's a picture (Maya screenshot), showing stages of morphing a sphere into a cylinder and then into a cube.



Topologically, each object in the picture is a sphere (2 poles, one stitch). But by moving the vertices around, all manner of shapes are possible.

The picture obviously is not a direct analog to Zbrush, since the objects are NURBS surfaces, not polygons. But the same relevant principles apply.

SL's tag line is "It all starts with a cube." Well, for sculpties, it should be "It all starts with a sphere."

Yep! Good to know about this. Thanks.


Thanks for that image; that's enlightening. OK, I'll try starting with a sphere. I had some luck with a sphereinder, but again my mesh ended up a bit strange, and I got some odd results. I think if I just take more time to move my vertices carefully, I won't get in so much trouble. I'm not used to using these 3D primitives in ZBrush; I've usually done my basic modelling with zSpheres or other zTools. So this is a good learning experience! I imagine I'd have an easier time in Max, but I've been on a ZBrush kick, and I find it more fun...and I do this for fun, not a living.

Anyway, here's a look at my first effort at a comforter, based on a sphereinder. I've got loads of polys on the edges of the comforter, but they're aligned funny, and I'm having trouble making a smooth edge. Note also the new textures, for the "fem" version of this bed. (My main business is animations, incidentally.) And note the little X in the middle of the comforter; that's the "pole" of the sphereinder. The pole actually doesn't look bad, provided you don't go crazy with your texture choice.

Word of advice after seeing that last picture: hide your poles. Your comforter model is a good example of how poles can be problematic when they're placed too obviously. While blankets do of course wrinkle in RL, they'll almost never wrinkle in that asterisk pattern you get around a less than ideally positioned pole. A better solution for that particular object would be to turn the sphere on its side right at the beginning, so the poles will end up on the dangling sides of the blanket, rather than right on top.

The picture below shows it in simplified form. The lower panel shows the object upside-down, so yo can see where the poles are located.

Sounds like good advice; thanks. I'll try hiding the poles that way now.

Same thing in ZBrush:



I started with just a 8x9 cube, squashed the cube down to make it flat. I then enabled X,Y and Z symmetry and manually shaped the object using the 'Move' brush. Finally, I smoothed it off so as not to cut my legs off when climbing into bed.

2K, that's how I prefer to model in ZBrush too; start low poly, then subdivide. I didn't realize we could do that with sculpties. I tried 8x9, shaped the basic model, and subdivided twice, which gave exactly 1056 points -- just the right number. And your converter accepted the .obj file, producing a sculpt map. But when I apply it in SL, I get a wacky shape. I tried inverting the sculpt map in Photoshop (CTL I invert), but that didn't help. Was I wrong to subdivide the model?

Here are two images: the sculpt in ZBrush, and in SL.

You need to use UV reliant converter like Maya if you wish to model from a low resolution object.

My converter and Wings's converter doesn't rely on the UV Map at all. They just map the vertices directly and so it's essential that the vertices are stored in an orderly fashion.

Oh, re-reading your post, 2K, I realize you were probably just showing me an example of how to hide the poles -- not suggesting that I try making sculpties with 8 x 9s and subdividing. Rats.

Actually, that points up my biggest problem with using these 3D primitives -- there are rather more polys than I like to handle when making my initial sculpt. I have all sorts of trouble just making a simple U-shaped basic model when I have to push so many vertices around. The deformation tools help to flatten, but the "bend" tool confounds me, and I end up pulling countless vertices by hand, making a mess in the process.

I'm going to try it in reverse -- make a 32 x 33, then reconstruct subdiv twice to get to a low poly shape, model as before, then see if I can export.

Edit: Just saw your latest post. Understood, thanks.

Ooooh! That sounds interesting! I never knew about that option!

Let me know how you get on, Ricky!

Heh, so much for that idea. There's no getting around it, it seems: I'll just have to learn how to shape a 32 x 33 more efficiently. I can do it by moving vertices and deformation, but it takes me a long time. Maybe I should just use The Force, fire up the Standard brush, and sculpt on clay, which is after all a very un way to use ZBrush.

Edit: FYI, your converter did make a go of it, but somehow reconstructing the subdivision must mess up the order of vertices. Oh well. It was worth a try.

I think this statement is misleading. The cylinder topology is a generalization of the spherical topology, so it can represent anything a spherical topology can, plus more.

If you have a cylinder topology and you want to make it emulate a spherical one, you draw all the points on the open ends to the same location. But if you want to close off the ends in some other way, you have that flexibility, too. I would think the cylindrical topology would be preferable to the sphere for a comforter. On the other hand, a plane topology is probably better still, since you don't really care whether you can see the comforter from inside the mattress.

Of course, the particular tools you use may favor a particular topology. Chosen, is there something about Maya and/or its exporter that accounts for your puzzling (to me) strong bias toward the spherical topology?

Omei, you're absolutely right. A plane or a cylinder would work just fine for something like that comforter. The plane would probably be best, in fact, since there won't be so many wasted hidden vertices.

The main reason I'm partial to spheres is that, at present, the sphere is the only sculpt type that is officially supported. Qarl has said many times that if you use any of the other types, you do so at your own risk, as their implementation conceivably could change before they become official.

That already happened once with spheres, and it was a huge pain. When sculpties first hit the beta grid, we all got really excited (of course), and everyone spent weeks making tons of them. Then when they were released onto the main grid the map orientation was changed, and every pre-existing sculpty ended up inside-out (coincidentally, just like the mattress in the OP here was inside-out). That sucked. I've learned the hard way that it's best not to get too heavily invested in anything unofficial.

Also spheres make for relatively easy teaching. But when the other types do become official (and it looks like they will very soon), I'll certainly adjust my recommendations accordingly.


As for the "misleading statement", well, if you take it out of context, then yes, it could certainly be misleading. But when you account for why I said it, there's not much room for misinterpretation. The OP was asking how to get rid of poles, in pursuit of Zsphere-type topology. If you use a cylinder to avoid having poles, then you won't be closing the top and bottom. If you snap the top and bottom rows of vertices to the center to close the holes, then you are creating new poles, exactly the opposite of what the OP was asking for.

You're of course correct that you could snap the top and bottom vertex-rows to form lines instead of points, and that would actually work really well for something like that comforter, but it still wouldn't achieve what the OP was asking for. So it wouldn't have been a direct answer to the question, just an add-on.

With sculpties, there is no practical way to acheive the poleless Zsphere-style form the OP was looking for. If you want a closed sphere, it's going to have poles. That was the relevant point.

That said, you're right that I should have been more clear. Sorry for anyone confusion, everyone.

I appreciate that clarification, Chosen; I didn't realize that only spheres were officially supported. Given that it's not all that hard to flatten and otherwise deform a sphere, I'll stick with that for now. I'm going to be selling this stuff, and I hardly want to deal with returns if the prims suddenly turn wacky.

My only trouble is, as you say, dealing with all the pesky hidden vertices. I really really wish we could start with a low-poly version of the prim and then add detail after we've made our basic shape. I don't have any trouble flattening the sphere using the ZBrush deformation tools. My problem is folding the sides down without making a mess of the mesh. In the attached shot, the poles are hidden at the bottom of the hanging part of the comforter. But sometimes I see a couple anomalies in the side of the comforter, doubtless because of vertices that are inside-out. Oddly, the anomalies don't always show -- the model looks OK here, if a bit puffy on top.

Why would a plane work? I know it would eliminate the hidden-vertices problem, but it wouldn't have any thickness, would it? I'd end up with a gossamer sheet in SL, no?

I should toss a few Lindens to all you guys for giving me all these free sculpty lessons.

In a sense, every SL prim, sculpty or traditional, consists of gossamer sheets, because only the surfaces, not the 3D interiors, really exist. And even the surfaces of a "solid" prim are only "half" a surface in the sense that you can see them from only one side. You can readily see this if you move your camera to a position inside a prim -- the prim will disappear. But since normally, one has no reason to move their camera inside a prim, this isn't particularly jarring.

If you used a plane for your comforter, you would tuck the edges of the plane into the bed, so that under normal usage, one wouldn't see that the underside of the comforter isn't there. The advantage of the plane is that you have more vertices to work with to model the visible surface. Whether that is a big win or not depends on what you are comparing it to. If you made your current comforter as I think you have, by flattening a sphere and then contorting it in "obvious" ways, you are probably "wasting" about half your vertices in modeling the comforter's underside, which no one will normally see. If, on the other hand, you've deformed the sphere enough that there are essentially only a few faces stretching directly between the lowest visible edges of each side of the comforter, then switching to a plane wouldn't buy you that much.

Chosen, I know I've seen you write that before, and yet I have never heard it from Qarl, nor seen him write it anywhere. Do you happen to have a source for it? I would be interested in seeing the context. Certainly, there have been many, mostly un-announced, changes in sculpty details beyond the one you mention. And there are more coming.

But as a programmer, I can't envision any plausible changes to the "advanced" topologies that wouldn't affect spheres as well. So my take on it that is the only significant way these are not "officially" supported is that there is no UI for setting the scupt type. But then, I have no inside information, and I have been known to be wrong.

Actually, this is what I've got -- just a few giant polys on the underside of the comforter. But I still like the idea of a plane for a different reason -- I'm having trouble bending the sides of my flattened sphere without creating inside-out geometry. Putting the pole at the end of the bent sides only makes the bending task more challenging. ZBrush has great deformation tools (including a bend tool), but the one thing I can't figure out how to do is to bend 1/5 of a flattened sphere without creating all sorts of odd distortions. Perhaps I'm missing something?

Bending a plane would be a lot easier. Actually, bending the sphere would be easy if I could start with 200 polys instead of 1000.

I'm gonna upload my new converter later. Life is gonna get a little easier.

Good question, Omei. I don't have any written source to give you, sorry. I'm just reiterating things that came up in coversation back around the time when sculpties first hit the grid.

You may well be right that there won't be any changes, but none of us can know for sure. Plenty of people have been willing to take the risk, obviously. I'm just not comfortable chancing it myself, and I'm also not comfortable suggesting anyone else do something I wouldn't do, so I continue to recommend spheres for all things.

Anyway, just a guess, but I'd be willing to bet there are more reasons than just slow UI development that have held up the other sculpt types from becoming official. Surely it can't be that challenging to add a three more items to a dropdown menu. But I'm not a programmer, so I have no idea. And if I were, I probably still wouldn't have any idea, since I'm not a Linden programmer.