New to Sculpties -- please explain the cause of this...

Hello,
I just started playing with Sculpties yesterday. As a simple test, I elongated a 32 X 31 sphere, and exported its Sculpty 128 X 128 texture from Wings 3D. Upon uploading to sl and applying the texture, I found unexpected distortions to what I expected to be a uniform object like the original from Wings 3D. Please see the included attachment that shows the chunky ends and slight torsion to the length. The wireframe (shot in sl) reveals how the vertices are offset (looks like sculpty prims end up with vertices, don't they?)

My questions are:

1) Did the software or I do something wrong? How can I get it to work right?

2) If I did this right, are there some rules of thumb that can help avoid these distortions?

3) I see tutorials on how to model for sculpties in specific programs, but I don't see any that discuss the finer issues of sculpty modeling. I don't need to learn a program -- just what to look out for to increase a good outcome. Are there any tutorials along those lines?

Thanks!

Not sure but if you can light it, I'll test it.
No sculpties are really smooth, even standard prims. Take a close look at them.
Use smoothing options on the mesh before baking the map. It helps a bit.
One test just isn't enough. Try 10 then post if you still have problems.

Thanks for your response. What do you mean by "light it?" I'm happy to send a file to you, if you want to test it. I understand that sculpties are not really smooth, but this is dramatically chunky at the ends. What do you mean by 10 tests? Re-upload the same texture 10 times? Apply the texture ten times? Something else? Thanks for your clarifications.

Did you upload it losslessly? Sculpties are very specific.. without a lossless upload they can become rather deformed. Make sure the sculptmap is small (64x64 is best, I generally use 128x128 I believe) and use the in-client lossless upload or su\\use lossless uploading with SLImageUpload.

It should help considerably if you aren't currently using a lossless version.

if anything, you've made a great looking joint. much better than the ones you see noobs walking around with anyway

Thank you, I was just quietly reading Building Tips and have now spewed diet coke on my keyboard.

Thanks for your thoughts on this. Unfortunately, in this case, lossless made no difference. I do know about making sure to use lossless, so after I tried that and it failed, I tried the other. Both came out looking the same, actually. I made sure to test that before I posted this query.

Are you saying I should use 64X64 instead, even though you use 128X128? I thought I would get finer detail with 128X128.

Doh! You've got a good point!

Lossless uploads smaller better is all. A 128 can give more detail technically, but it wont upload as 'perfectly' as a 64x64.

Lossless made absolutely no difference? You sure you actually uploaded losslessly? Were you using the SL uploader of SLImageUpload?

The thing is, on a successful lossless upload I've never seen pinching on the ends to that degree, so I honestly am at a loss

Later tonight I'll make a side-by-side comparison for you to see.

Sounds good ^_^ hope this gets figured out

The problem is caused by the 8 bit precision of sculpties and there's absolutely nothing you can do about it.

To demonstrate - find a 3D modeler that will let you round down your vertex positions to integers and watch what happens to the ends of your cigar/joint, you'll get the exact same results.

In the early days, Qarl said that LL may consider using 32 bits for sculpties instead of the current 24 bits. But I've no idea on whether they're still considering that. I suppose it all depends on how many threads there are from people with wrinkly cigars.

If only I wanted to make cigars!
No, I made these to test how sculpties handled a narrow, round-tipped shape. I have much more complicated things to sculpt, but I wanted to see the limits with a simple test.

Now that I know there is nothing I can do to make this better, I need to ask,

1) Are there some rules of thumb that can help avoid distortions as I construct meshes?

3) I see tutorials on how to model for sculpties in specific programs, but I don't see any that discuss the finer issues of sculpty modeling. I don't need to learn a program -- just what to look out for to increase a good outcome. Are there any tutorials along those lines?


(I'm including the tests I did since my last post. One shows the similarities between no compression and lossless compression. The other shows a comparison between 64 X 64 and 128 X 128 texture output, and these are both losslessly compressed.)

Looks to me like your lossless is borked. Should look very different, not essentially the same.

Anyway, there really isn't a 'generic' sculpty tutorial. There is an introduction to ohw they work and what they are, it's in the 'sculpted prim tools and tutorials' sticky up at the top of this forum, near the end, and thats about the closest to what you're saying it seems

THe problem is that every program handles things differently, so there will not be a set of generic rules. With wings 3d you generally want to stay at 32x31. With nurbs you can use any nurbs model, but you have to know how to work it properly. I don't know about maya, 3ds max, and blender as I haven't really used them. With things like sculptyspace there are no worries, it will always work pretty much.

If you want a set of generic rules well..here you go:
--------------------------------------
You cannot use super-high-poly models and expect super detailed sculpts. You lose far too much detail, as there is a limit to the vertices in a sculpty (I think.. theres a limit to SOMETHING lol).

You cannot use more than one object in any modeller and expect a single sculpty, it has to be from one surface.

You can't start with a cube or anything similar, unless it is proven to be a single surface. Most cubes are actually 6 planes and such, so it doesn't work. Therefore most people start with either a sphere or a plane.

You can make it look like more than one object, but without lossless, it will look like candy boiled too much then dried (A big messy mass)

You have to use lossless for good quality sculpts, otherwise they look lumpy, and details are lost, and sometimes it looks nothing like it should at all.

--------------------------

In all seriousness, it looks like you aren't uploading losslessly, whether it's your error or the error of whatever you're uploading with.

Are you using the in-client uploader or something like SLImageUpload?

To rule out lossless uploading issues, try previewing your sculpty in Sculptyspace. http://www.sculptyspace.com

As 2K Suisei said, It looks to me like 8 bit precision error. Your vertices are too close together to be represented accurately with 8 bits, so they snap to the nearest 8 bit position, and you get this ripply bumpy effect. Making sure that your sculpty fills the whole possible bounding volume can help reduce this effect (you can check this in sculptyspace by hitting B to view the bounding box). But on something long and tapered like this, you're going to have to go in and tweak the ends as there just isn't enough precision.

I really should learn about this 8 bit thing.... >.>

Its pretty simple. Each vertex in a sculpty has an 8 bit X,Y,Z position, 2^8 gives you 256 possible values from 0-255.

So if you're mapping a range of floating point values to a sculpty, you can only have 256 possible positions along any axis. Anything lying between two possible 8 bit positions has to be rounded off to the nearest one. If you have a model in your graphics program with a lot of fine detail, you might be positioning vertices in between possible 8 bit values and they will have to be moved to be represented as a sculpty, so the result won't look like you intended.

Ah okies cool..

What I'm not understanding then, is that if (s)he used a 32x31 sphere to start with for that joint up there, then why would it change it so much, even if it's having some odd interaction with the 8 bit positioning? Seems like with only that many vertices it should work generally fine any way

Its got nothing to do with the number of vertices, but the position of those vertices. It may be a little misleading because the actual sphere you start with can't be represented exactly by a sculpty either. Generate a sphere in sculptyspace and take a look at the end caps. SculptySpace generates a sculpt map and then displays the mesh based off that, so the result is always correct - you'll notice that you can't get the last ring to look perfectly circular.

Ah okies yeah..and even with a lossless upload there will always be a tiny amount of pinch it seems too... okies cool, I think I understand a bit better now ^_^ you're my hero


And sorry to Sky Hye for the temporary thread hijacking!

I did my testing in the beta grid. I used the sl client upload window with lossless compression box checked.

Unfortunately, I can't use sculptyspace. I use a mac.

I don't know iflossless on beta is borked now lol... try uploading just once using SLImageUpload on the main grid, and see if it helps. Make sure the top box for lossless is checked.

heres the link to the uploader

http://wiki.secondlife.com/wiki/SLImageUpload

I've never had a problem with it

You didn't hijack. This talk helps me know what to look for as I build my meshes.

Unfortunately, I can't use SLImageUpload. I use a mac.