New to SL - Experienced in 3D. Symmetry workflow? Sculpty workflow example?

Hi all,

I experienced SL a while back and I've just made an account. Having fun already. Good times and whatnot.

I really want to sink my teeth into things. I'm mostly through the Ivory Tower and I want to know what the typical workflow is for SL users for creating symmetrical objects. I don't mean the "stretch symmetrical" tool, either.

I mean, what do you typically do when let's say for example you're modelling a rough humanoid shape and you've got one arm finished. Is there a way you can quickly and automatically duplicate this arm of prims on the opposite side of your object (even if you have to do it in another object) instead of doing a lot of measuring and laborious farting about and building everything twice?

Also, when making an obj to mold into a sculpty, what are the poly and scale constraints? Any specific behaviors (Sub D for example) to expect? Where can I find a really good read explaining this sort of thing and what I need to feed my OBJ file through to get the desired product?

When I do so, what then in terms of UV? Can I make a UV for the sculpty based on my obj file or do I need to base it on what SL gives me as a UV template for the prim the sculpty will be made around?



Thanks for your time. :3

if you can convince someone to drop a prim mirror script on you, that's about the fastest way, but it's also quite easy (though slightly less fast) to use the reference ruler mode of the build tools... select a single prim, hold shift then drag the handle in move mode to where you want it to be (leaving a copy behind) then rotate into position.
you can also use reference mode, which can be helpful in aligning objects along the same axis as well as matching it's dimensions by selecting your reference prim then pressing shft+G (to set the prim as your reference), and selecting the prim you want to edit afterwards... all the rulers and directions will then be based on the reference prim (ruler 1.0 will equal the size in that dimension for the reference object for example... great for size matching)

32x32 vertex grid, size constraints would be ~10m in it's largerst linear dimension (~17.3m for corner alignment IIRC) or possibly larger with a megaprim.

the sticky up top I think has some more of the technical details

I have no tutorial at hand, how you can convert an arbitrary object into a sculpty. Whenever this question occurs, the most given answer is:

"Redo the sculpty from scratch."

This is due to the very special constraints on sculpted prims. In many cases a conversion will not be possible. In many other cases it may be possible with a significant amount of work. In rare cases an easy and straight forward conversion is possible.

For instance: In Maya it seems like you can fully work with NURBS. For blender there is a "NURBS to Sculpty" converter available:

http://blog.machinimatrix.org/nurbs2sculptie

A full workflow example for how to create and texturise sculpted prims (using blender) is given in form of multiple videos on the machinimatrix site.

http://blog.machinimatrix.org/video-tutorials

More advanced techniques can also be found at Keira's Youtube channel

http://www.youtube.com/user/BlenderSL

Other tools and pointers can be found here:

http://wiki.secondlife.com/wiki/Sculpted_Prims


Take care to read that as "32*32 faces"! BTW this was the standard size until recently. Since a while other mesh ratios are allowed, but the maximum facecount may not exceed 1024. Some ratios are:

64*16
128*8
256*4

Other ratios are possible. Smaller meshes are also supported. The smallest mesh i could ever import to SL was a 4*4 faces mesh. But beware, LL have not yet fixed a bug which occurs with lossless import of SMALL images. Here is some important extra information about that:


http://jira.secondlife.com/browse/VWR-8551

Since the vertex locations are transported via UV-textures, the most important issue is how image pixels are mapped to actual vertex positions. The rule of thumb is:

use an image size of [2*x-faces, 2*y-faces] Other image ratios and other image sizes will be mapped and thus loss of precision is the effect. E.g. for a map of 32*32 faces, use an image of 64*64 pixels. The exact mapping of which pixels in the image will determine wich vertex in the sculpty is explained in more detail here:



have fun
Gaia

Sorta confused here on the constraints. The converter, I get. The texture format (XxY PNG sculptymap), I get.


- Do you basically just model with the map indicating vertex position using color or is it a glorified bumpmap?

- What are the constraints in 3D? Is it 32x32x32 vertex subdivided prim which is then sculpted in nurbs to create the ideal shape or something like that?

- I'd like to confirm: the default behavior is NURB-like so using a Sub-D editor is ideal.

- Can I import an obj into a compatible package then just export as a sculpty for SL or are there any other special constraints to be taken care of?


I'm really surprised the tools in SL for editing them aren't comprehensive. It's kind of irresponsible for them not to include a decent editor to get you off the ground for a property format or provide a converter that'll take it from an industry standard format to the property format and back again - or to explain exactly what the constraints and environmental behaviors the modeler should expect.

I expect this from the Linux community, not SecondLife.

Ah well. Enough griping. No need for it really.



It'll all be explained soon... I'll probably put together a video tutorial or something to get new folks off the ground on youtube since this has really bugged me and there's not much out there beyond the videos explaining the basics of blender on SLBlender (tbh as powerful as blender is, it makes LightWave look super-user friendly which is scary).



Thanks for your time :3

Just so you know, it doesn't have to be PNG. TGA or BMP will also work.




It's actually a displacement map, if you want to get technical. But no, you don't model with it. Model by moving vertices around, just as you normally would (but steer clear of extrusions, splits, appends, or anything else that would change the topology or disturb the UV layout).



All (non-oblong) sculpties are simply a 32x32 grid of quads, a perfect rectangle, which is then bent or folded in 3D space to create whatever shape you want. The best analogy is origami. You can bend and fold a piece of paper to make a bird or an airplane or a fortune teller, or whatever, but when all is said and done, it's still just a rectangular piece of paper.



It's NURBS-like (no such thing as "NURB", by the way; the S is the most important letter) in that everything is ultimately rectangular. I'm not sure why you're thinking in terms of Sub-D's which, like their polygon cousins, can be completely free-form.




In most cases, an arbitrary mesh will not be directly sculpty-compatible. Sculpties require a perfectly uniform UV layout, and a mesh that is unfoldable into a perfect rectangle. That's not the way most models are made.

The best way to create sculpties is simply to deform existing primitives (spheres, cylinders, toruses, or planes). Remember, origami. Take a plane, curve it in 3D to become a cylinder, and it's still just a plane in 2D. Pinch the top and bottom to create a couple of poles, and now you've got a sphere in 3D, but in 2D it's still the same old plane. Push and pull the vertices around so the sphere becomes cuboid, or a human head, or a whatever else you might want, and you've got yourself a sculpty. But again, the whole thing is still nothing more than a plane in 2D.



I wouldn't call it irresponsible. I can see how it might appear a little incomplete, if you're new to it, since the concept is a bit different from what you're probably used to. But "irresponsible" is kind of a strong word. Linden Lab is under no obligation to create every conceivable tool that might be useful in creating content for SL.

Is it irresponsible that there are no built-in texture editing tools? Or sound editing tools? Or animation tools? Or language translation tools? Sculpties are no different. Keep in mind, SL can do about a million different things. Exactly how big do you want the viewer to be? Would you really want it to try to tackle everything, all by itself.

The comparison I usually use for this sort of discussion is that the viewer is in almost every way analogous to a Web browser. If you want to create very simple content for the Web, like the text we're composing on this forum right now, then a browser can do the job. But if you want to create anything more complex, then you need external tools like Dreamweaver, Flash, etc.

By the same token, if you want to create very simple content for SL, like a house made out of cubes, then the viewer is all you need. But if you want to texture the house, make the front door creek when it's opened, and sculpt a nice sofa for the living room, then you need to use external tools.


One thing that is important to remember is that sculpties are little more than a hack. They're sort of a placeholder between SL's long existing system of parametric solids (prims), and full blown mesh support. They were the brainchild of one enterprising Linden, named Qarl, who reasoned that they'd make for a relatively easy way of expanding SL's content display capabilities without having to make any fundamental changes to its architecture.

The capability to import textures was already there, as was the ability for the viewer to draw polygons (obviously), along with a system of culling LOD over distance in a predictable manner. Qarl simply created a bridge between the three.

As far as the server side knows, every sculpty is just a primitive. Notice they all have the same type of bounding box, regardless of their visual shape. All it took to make sculpties work was simply to build a displacement map interpreter into the viewer.

Sculpties are a stopgap, nothing more. They were never meant to be a permanent solution. Sooner or later, full mesh support will be implemented, and sculpties will no longer be necessary.

In the mean time, we have to give Qarl's resourcefulness due credit. It was heck of a clever solution, a testament to "less is more" type thinking, which is really what SL has always been about.



You're absolutely right that LL could (and should) do a better job of documentation. While they do try, this has been one of their biggest weaknesses since day one. However, sculpties are pretty thoroughly explained in the sculpty wiki. Did you read the information over there? http://wiki.secondlife.com/wiki/Sculpted_Prims




Oh, well in that case, welcome to SL.




Since Blender is your tool of choice, have you watched Gaia's machinimatrix videos? They're very good.

sort of that. 24 bit rgb plus 8 bit spare (currently mapped to the alpha channel) maps to x,y,z 8 bit for each axis -> 256 locations along each axis.

No, the sculptmap tells exaclty where the vertex locations are supposed to be in world. So no NURBS behaviour in world, but its easy to convert NURBS to Sculptmaps as they use the same backing technology (bending a plane, not sure if that is what a 3D expert would name it though)


Not to my knowledge. Maybe the archipelis designer... (not sure)

well, an in world editor would have certain advantages, but due to the nature of sculpted prims i guess, the better option was to let their construction be done externaly. there are enough good 3D tools around to support such technology. It may be questionable why they have chosen that special format, but to all i know, it was the best they could do at the time when they invented sculpties. remember... 2 years ago, there where only prims available...

Big Protest I think there are a bunch of good explaining videos and other tutorials around. But getting a comprehensive tutorial/reference guide on sculpted prims is a good idea ... yeah!

ups. Chosen has won the race again

The origami metaphor is a really really good one. Sort of like changing the shape of a table-cloth -- But then what do you do with the end?

Can vertexes be joined at those ends or do you need an open end at the other side which the thing just "makes sense of"?

Are there any examples out there of topologies before the sculpty process that have been made in this fashion that I can see?

I'm having trouble wrapping my head around it - I'd have to start with a flat mesh and gradually re-sculpt it in three dimensions into something of complexity...

Anyway, thanks.


Edit:
Just tried Sculptypaint and I can't mentally make sense of what the various curves and such are actually for. Grah.

If you can find a few minutes to take a look at some of the links i gave you above, you will get all answers... In particular you might get most out of this one:

http://blog.machinimatrix.org/2008/07/14/sculpted-prims-for-the-blender-purist/

have fun
Gaia

Osaka, good questions. Good explanations Chosen. Gaia's videos are great.

Also, real irregular mesh imports are soon coming to SL. 'Soon' being the keyword and undefined.
http://nalates.wordpress.com/2009/08/24/preview-of-coming-things-in-second-life/

As well as shadows and diffuse lighting.

Gaia, how do you get those links to work?

The four stitching types determine what happens to the ends (and the sides). Here's how they all work:

Sphere - The top and bottom are collapsed to poles, and the sides are joined as a seam.

Cylinder - The top and bottom are left open, and the sides are joined as a seam.

Torus - The top is joined to the bottom as a seam, and the two sides are joined to each other as a second seam.

Plane - Everything is left open, no stitching at all.




Create the same basic four primitives in any traditional modeling program (i.e., not Zspheres from Zbrush), and the construction will be nearly identical, if not entirely identical to how SL does it.




You CAN start with a flat mesh, but you don't have to. The majority of sculpties are created from spheres.

Here's an example I've posted sever times before, showing how a sphere can easily be deformed to become a cuboid. It's aimed at Maya users, so the objects in the picture are NURBS, but you can do the exact same thing with polygons if you're using a different modeling program.



I'd suggest you take a good look at the objects in the picture, and then practice making them. Once you've done that, you'll very likely be in a better frame of mind to start to see how the same techniques can be employed to create just about any shape you can think of.





I've never used SculptyPaint. Can't help you there, sorry.

Use the tag instead of the url tag.
If the url does not contain a query string, add a questionmark at the end of the url.

More interesting information about forum markup (e.g. how to add a link to an embedded image) is here:



cheers,
Gaia