Beginner sclupty question.

Ok I've just started learning sculpties. I'm using maya5.5 and got the export mel script from this wiki - http://wiki.secondlife.com/wiki/Advanced_Sculptie_Exporter_From_Maya

I created a basic NURBS Plane surface and deformed it to see how it reacts. Here is a picture of it in maya. - http://img10.imageshack.us/i/63370246.jpg/

And here is a picture of it in SL - http://img8.imageshack.us/i/36016352.png/


Here's the steps I took -

1 - deformed NURBS
2 - deleted history by type
3 - froze transformation
4 - reset transformation
5 - deleted histroy by type
6 - executed export script
7 - uploaded image to SL

Anyone have any ideas on why the sculpty looks deformed in SL and not like it looks in maya?

Thank you

How many spans and sections are you using? It should be 16 by 16. If you are using more, that could be why.
I'm sure Chosen Few will be by shortly to help, but I just thought I'd throw that in there in case that is the cause.

Hath my fame preceded me?



Honor, you've got two main problems going on:

First, Harlow's right (and not just in predicting that I would reply). You've got too many spans. If I'm counting right, your surface is 32x32. Generally, 16x16 is as high as you want to go. Otherwise, the resulting in-world mesh won't be able to reproduce all the detail of the NURBS source model. Remember, every (non-oblong) sculpty is 32x32 quads in-world.

If your surface were totally flat, then 32 spans would translate perfectly to 32 quads. But as soon as you bend the surface even the slightest amount, spans can no longer tesselate directly to quads. NURBS are based on curves, after all, and it takes an awful lot of straight-edged polygons to simulate a curve.

Generally speaking, for best results with sculpties keep the span to quad ratio at 1:2. For a square sculpty, that means 16x16 spans will translate well to 32x32 quads. For oblongs, go with 32x8 spans for 64x16 quads, and 64x4 spans for 128x8 quads.

Second, keep in mind that LOD rolls off over distance. From close up, a square sculpty is 32x32 quads, but move your camera out a bit, and drops to 16x16 rather quickly. Go out further, and it drops to 6x6. (If you're wondering why 6x6 instead of 8x8, the answer is it used to be 8x8, which was more logical. But they cut it to 6x6 to reduce rendering lag. 6x6 is 36 total quads, which is a reduction of almost half, compared to the 64 quads of 8x8. The powers that be at LL figured distant objects are going to look like lumps no matter what, so there was very little to lose and a lot to gain by nearly halving the poly count of those objects you can hardly see anyway.)

When making sculpties, it's super important to think about where the reduction points are going to be. If you want a particular feature to be more LOD-proof, then pile more vertices in that area. Features that won't be affected by culling should be given as few vertices as possible.

Right now, you've got all your isoparms evenly spaced. That's not really a good idea. Notice you've got something like 9 or 10 spans in the upper area of the model, above where the protrusions begin. For best LOD-proofing, you should triple up the isoparms at each corner. The bevel should be just a single span. The corner should be very compact spans. The flat part should be one large span, and then the next corner should be two small ones again.

Take a look at the following image. On the left is your original. On the right is a quick sketch I made in of where the isoparms would best be placed. Notice there are three at every corner, and none in between the corners. Not only does this make for much sharper definition in the source model, it also helps ensure that the corners won't disappear when the camera moves away.



Note, I did the sketch without regard to the total number of spans, just to illustrate the point of how corners are best made. I would not recommend trying to make a shape as complex as yours out of just one sculpty. Technically, it CAN be done, but it won't hold up well against LOD culling, so it's not a great idea.


To summarize, use less spans, pay careful attention to where you put your isoparms, and you'll be fine.

That was an awesome explanation! Many thanks! I most deffinately appreciate the time it took for you to right that out. I'll do some more expiramenting now and see what I can come up with. I suppose if that particular shape doesn't work out so well, what I could do is make one with a high isoparm count for texturing and lighting and a low isoparm model to apply them to.

OK maybe spoke too soon. I created a default nurbs sphere. at 16x16 spans and then exported it. No tweaking at all. When uploaded I got a sphere with a chunk missing. Making it look like a pacman.

maya pic -- http://img132.imageshack.us/i/84361329.jpg/
SL pic -- http://img269.imageshack.us/i/78429547.jpg/

It has me stumped. I also tried 8x8 spans with the same result.

Make sure Correct Orientation is checked in the sculpt map exporter dialog. What you're seeing is the result of the map being rotated 90 degrees from how it's supposed to be. It's trying to put poles where a seam should be, and a seam where the poles should be.

If you want to know the reason why Correct Orientation is an option in the exporter, it has to do with history. Back when sculpties were in beta, the mapping was 90 degrees from what it is now. If memory serves, there was a brief period in which the old orientation still existed on the beta grid at the same time the current one was first being introduced on the main grid. Or maybe it was the other way around. Either way, it made sense back then for the rotation to be switchable. Fast forward a couple years to today, and that toggle really should be done away with, since time has proven that the current rotation is here to stay. But nobody's updated the exporter, so we've still got all the old switches, lights, and knobs.

If you don't see the checkbox for Correct Orientation, it's because there's a scrollbar in the way, due to a typo in the exporter script. Search the script for the word "scrollable". If there's a 1 next to it, change it to 0. Rerun the script, and the scrollbar will go away, exposing the checkbox.