Sculpties very lumpy - What am I doing wrong?

As you see on the attached picture, I modeled a couch in Maya (only made of nurbs spheres). Couch looks good and straight in Maya even on low settings, but looks very lumpy in-world.

I MUST be doing something wrong, but reading all the topics I can't find the solution. I even used the option Rebuild in Maya to turn vertice count down. That helped a bit but not much.

I really don't understand. Most parts of the cushions in the couch are very straight, especially the front of the back cushions in the picture, but they still turn out lumpy. They are not even near to the very nice straight cushions on the example couch, see attached pic 2.

I read Chip's solution for 3DMax and the further explanation of Johan Durant for Maya (transfer polygon attributes), but I don't know how to do it in Maya.

Am I doing it all wrong by using only nurbs spheres for modelling? Please help me. I am reading a lot, but can't find the solution.

honestly, your couch looks very good. all i can say is each prim is limited in its detail, so maybe you should use more prims. maybe one for each cussion, so more detail can be focused into each part

Thank you Fa for giving me a chin up. I needed that. But in-world it is really ugly and by no means near that example couch. That couch too was made with very few prims, so it should be possible. But how?

hehe i think the lumpiness makes it look soft and comfy!

i believe that example couch is about 7 prims, and it's not as detailed as it looks. like chip's single prim head sculpts, it has fake baked lighting textured onto it also, making it look more smooth than it is. i'm not sure how you do the baked shadow textures, but i'd love to get into that myself maybe someone else can chime in with a good tutorial link for baking the textures for these things.

you are not doing anything wrong really. using 64x64 or 128x128 but please don;t use 128 unless you have too. what you are seeing the the compression of the sculpt texture. this is very common. the sculpt is never exactly the same at what you see in your editor.

It's probably the JPEG compression skewing your vertex locations. Save your sculpt texture from SL, then compare it with the original image you uploaded and note the subtle differences.

I think your couch looks great. The lumpiness is typical of all the sculpties I have seen so far. I think we are going to get accustomed to (and hardly notice) the lumpiness just as we have with seams on skins and prim skirts showing the butt crack and all the other charming quirks of SL. I look at your sculptie couch and see a nicely shaped couch making excellent use of this new feature.

And maybe we should call them "lumpies" instead of "sculpties"

I know you were trying for a one prim version of that couch and that was great. But I agree that what you produced isn't ugly. Unique yet. I would buy it.
I believe as well that compression needs to be turned off for the smallest levels.

Yours is great, Paulo! And ONLY 1 Prim!!!
All of SL is a tradeoff of the constraints of the program vs. our imaginations. Your couch is a wonderful thing!

As for the lumps?
You should see my RL couch!

Wow. I feel really honoured and surprised by all your kind words and encouragements. Thank you very very much. This gives me a lot of inspiration to keep trying and share any progress I make.

Because I think there must be a trick or a combination of things to reduce the lumps. Maybe we'll even discover it by accident lol.

But one thing I'd like to ask once more: is my apporoach with using only nurbs spheres the right one or should I just model with polygons or other nurbs/subd-objects and try to fit them all together somehow?

I think your couch looks great. I don't know if it is possible to avoid "lumps" at the poles of the NURBS sphere mesh. The great sculptie couch that you attached an image of incorporates the bulges of the NURBS sphere poles in its design. You could do the same or cover it up with another prim. If we get lossless compression of the sculptie mesh then maybe we will be able to manually edit the mesh and remove these artifacts.

The sculptie renderer seems to smooth out edges (curvature discontinuities) in the mesh. This seems to be happening between your cushion sections. I use multiple sculptie prims to get sharp edges. Maybe the next generation of sculpties can use the alpha channel to encode the position of edges.

What else could we do with those 8 bits of alpha? Maybe attach multiple textures to a mesh and use 2 or 3 alpha channel bits to indicate which texture the mesh point should be drawn with. Maybe allocate 2 bits for shininess, so that a sculptie could have different degrees of shininess over its surface.

I'm not seeing any lumpiness really, but I am curious about the seams between cushions disappearing. I'm too lazy to actually count the isoparms, but it could be that you are using more sections than sculpties support and the exporter is ignoring details. Maybe you should try eliminating isoparms from the middle of the cushions, leaving dense geometry only where there are changes in shape, and see if that works any better.

Hi Johan, thanks for replying. I am now testing with removing/concentrating isoparms. I don't yet know if this will result in more straight surfaces in the sculpties, but what I do see is that removing isoparms reveils some irregularities in my model. I made the three parts of the couch with nurbs spheres and revolved nurbs curves, which makes it hard to get flat surfaces on all sides except corners, even when snap is turned on. The models in Maya seem flat where they should be, but apparently they are not.

As soon as I can I will place here a pic of the result with less isoparms on flat surfaces and concentration of isoparms in rounded corners.

I agree with Johan. My first thought upon seeing your Maya screenshot was "wow, that's a lot of isoparms". The best practice with NURBS models, whether for sculpties or not, is always to use as few isoparms as possible. You want to load up on them where you need high detail, like where your cushions curve, and eliminate as many as you can in the smooth expanses. To give you an idea of how few you actually need, it only takes three overlapping ones to make a sharp corner. For curved corners, you can take those same three (or even two in many cases), and just space them out a bit. Any more than that is overkill.

Think of isoparms kind of like SL prims. Only add them when you absolutely need them. Kepp the count as low as you possibly can.

The compression can also cause vertices to be misplaced. When you export, use a lossless file format. SL will compress to JPG2000 in a lossy format (unless this changes for sculpties). A flat surface may become not so flat.

I suggest to convert the mesh to nurbs. Where you inted to have a flat surface, check the how many vertices are in that area and minimize them. Try to move the vertices to the outer edges of the flat area you want to define, for example. You should be left with a flat face even when compressed.

xenius explains
/8/25/185425/1.html#post1521160

Update:

I experimented with lower isoparm count, but that seems to make the lumpiness even worse. Three pics attached:

1) Very low isoparm modelling in Maya and the way it turned out in-world.
2) Higher isoparm modelling.
3) Comparison between textures to see how the jpg-compression/import changes things. Left texture is original bitmap (64x64). Right texture is exported back out of sl (tga). I don't see many differences here, at least not in the extreme that it could explain the lumpiness.

I'm a bit clueless now on how to get sculpties without the lumps and bumps. Any other ideas anyone?

Well dayum, that is really screwy. You reach the limit of my knowledge here; it certainly looks like your sculpt images are nice and smooth and that the lumpiness is something wrong with how SL is shaping the mesh from the image.

Thanks anyway for replying Johan. Unless anyone else has an idea, my conclusion for now is that sculpties in their current form aren't suitable for making flat rounded surfaces. That is a real shame, because furniture (my business in sl) could be so much nicer with rounded corners.

Is there anyone who has a clue?

Try one of the previewers. If the problem shows in one of the previewers, it isn't on SL side or the compressed medium.

I haven't experimented with this yet, but I am wondering a very fine grained texture or noise on the texture might disguise the lumpiness? (Texturing the color on the surface, not the sculptie map.) You would need something with a fine grain to distract the eye from the lumps but not be too obviously distorted by the lumps.