[sldev] Sculpties: Vacuum-Forming, Skittering, Zone Linking

[Dale Mahalko]

 On 9/28/07, Argent Stonecutter <secret.argent at gmail.com> wrote:

> On 28-Sep-2007, at 11:27, Dale Mahalko wrote:
> > Tunnels and linked holes are technically impossible in a sculptie
>
> PRIM_SCULPT_TYPE_TORUS
>
But what if you need more than one hole, multiple interlinking holes, or any
number of holes? What if you're making a swiss-cheese sculptie? I realize
this rapidly becomes a discussion of topology and the limit of how many hole
configurations LL may offer in predefined prim types..


What's really needed is a way to arbitrarily define holes (or at least
seams) through a sculptie mesh so that the mesh can be literally cut and
peeled apart into independent flexible sections that are then wrapped and
shaped as needed to form potentially independent meshes.

This could be done by defining a particular color as a special code for
"make seam here". Since sculpties don't use the alpha channel for anything,
seaming data can be stored in there.


 Conceptual diagram: Sculpties Store Seam Data in Alpha

http://img211.imageshack.us/my.php?image=sculptiestoresseamsinalit2.png

So if you need a hole through the sculptie you simply draw an alpha-channel
line across the color vertex image.The points directly below the
alpha-channel form one edge around the mouth of the seam while the points
directly to the right (or directly above/below, if a horizontal seam on the
RGB data) form the other edge around the mouth of the seam. The adjoining
triangles across the seam are dropped and not rendered. To properly form a
tunnel, two seams need to be cut and the open ends of the seams go inside
and pass through the interior of the object. The open ends of both seams are
aligned and overlap to form a continuous tunnel.

Or if you want to just tear off a section of mesh from the sculptie, to be
used as a free-floating object always hovering in place nearby the main
sculptie, cut all the way around a large section of vertexes and then fold
the edges of that tiny patch together, so that the normals all face
outward to form a continuous shape. The square hole in the main sculptie can
just be pulled across and tucked shut to hide the cutout hole.

- Scalar Tardis aka Dale Mahalko
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