[Bf-committers] Edge Loop Selection in Meshes

[Andy Davis]

Yes, I'm still interested, thanks for the reply.

I think I will proceed with my original plan as it should get me familiar
with a nice slice of blender functionality.  However, I will immediately
follow on with a tour through Wings and see what of that functionality I can
bring to Blender.

-Andy

-----Original Message-----
From: bf-committers-admin@blender.org
[mailto:bf-committers-admin@blender.org]On Behalf Of Willian Padovani
Germano
Sent: Monday, May 26, 2003 9:26 PM
To: Blender Committers List
Subject: RE: [Bf-committers] Edge Loop Selection in Meshes


Hi,

On Fri, 2003-05-23 at 03:55, Andy Davis wrote:
> To be honest, I'm not quite sure that I understand the suggestion.  Can
> someone explain what a winged edge is, and what features it enables (I'm
> ignorant, not petulant).
>
> I'm working on a somewhat formal description of my algorithm, when I'm
happy
> with it I'll post it.
>
> -Andy

Took long to answer, hope you're still interested ... : )

Winged-edge is a way to represent a mesh, a structure to represent
connections between verts, edges and faces.  It's more expensive than
the naive ones, but it decreases the computation time of many operations
done on meshes, like finding the two faces that share an edge, etc. --
the adjacency relations.  A search for "winged-edge" should be able to
show you the specific structure.

The best way to get a feel for it is to try a modeler based on it, of
course.  There was one called Nendo, you can still find its binary for
Windows (and maybe some other architectures, I don't remember -- but not
linux, for sure).  I mention it because it has a nice demo system where
you can watch some models being constructed.  The modeling "paradigm" is
different from what many are used to, but you may enjoy the experience
and learn a lot from that.  It's like "can you, starting with a cube,
change it till it becomes what you wanted to model?".  Of course you
don't need to start with a cube, but that's the kind of ability this
modeling way asks of you (and returns as experience).

Inspired by Nendo, a guy wrote Wings 3d, a great open source modeler.
Personally, I think Blender and Wings complete each other, in terms of
modeling, so they are the ones I happily use, feeling no need for any
other modellers.  But it's written in an interpreted functional language
called erlang, that you have to download to be able to compile Wings, if
you don't find a binary for your system.  There's always one for
Windows, but the Linux binary isn't done by themselves and may be a
little outdated (good enough to try, though).  The site also has
documentation useful to learn how to model with it.

Basically, if you try it you'll see that some mesh modeling operations
are amazingly easy with its functions, while others are much easier with
Blender (which has its own extra features to help out, like curves and
surfaces, scripting, using animation for modeling, etc -- those things
in the old tutorials at blender3d.com).  As I mentioned, the winged-edge
structure doesn't like separate edges and vertices and if you're not
careful, your model will become problematic to handle until you manage
to fix the changes or undo them.

But specifically for selections, Wings has a big menu of options,
including a few for edge loops and rings, so that's a nice place to look
for ideas.

After you give it a generous try, following tutorials, you'll understand
why Chris Want suggested a winged-edge mode for Blender and why I agreed
completely, though it's not a trivial job to get all that in Blender.
It would be added in steps, of course, so it can be done.

--
Willian, wgermano@ig.com.br

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