Does anyone know of a file format which has, and an editor which makes use of, lines?

As I understand it, your average 3d model is a whole load of vertices, with each polygon basically stored as a list of vertices - "vertex 27, vertex 28, vertex 36", as it were. What file formats and editors will let me save and get data about lines (stored much like polygons), such as "vertex 7, vertex 13, vertex 17, vertex 22, vertex 29, vertex 42"?

If this is gibberish, tell me and I'll try to articulate what I want betterÖ we need an emoticon for "vague but expressive gesture". TWIM (= think what I mean)?

I have no idea if this is what you mean... but Meshwork explicitly stores edges as well as triangles...

Are you talking about paths?

Well, if you look at this funky cel-shading businessÖ it doesn't take an expert to see that it looks shite unless you're very careful or lucky or both, even though it clearly could look good. I want to be able to take a mesh and flag certain edges to always be drawn (depth test permitting), to avoid the way geometric detail is wont to disappear.

If you download the NeHe cel-shading example (here ), you'll see what I mean - for example, press space to start rotating and look at the hexagonal bits on the hips. They'd look much better if the model edges had outlines, rather than just the screen-projected edges having outlines (as it is at the moment).

Of course, I could determine the angles between polygons as I load the files, and flag only those edges with a sufficiently sharp angle, but I would lose any fine control, and I'd probably spend a lot of time tweaking models to convince my loader to produce the effects I'm after, and could spend obscene amounts of time and effort for results that are still uncertain, and probably wrong for any new model.

So, I was wondering if anyone knew an editor that'd let me store arbitrary numbers of lines of arbitrary length, along with the vertex and poly data? .obj format seems to have space for this functionality, so I suppose that's a possibility, but it doesn't do me much good without an editor that lets me do this.

Does that make more sense?

I'll look at meshworkÖ if it just stores all the edges, it's not what I want, but if I can attach some sort of data to individual edges (a single flag is all I really needÖ more might be nice), it should do the trick.

heh, yes, meshwork stores all the vertices and edges and presumably constructs the polygons from them - certainly, there's no explicit POLYGON section in the format.

SoÖ suggestion box remains openÖ

You could try Quickdraw 3D's 3DMF format. It supports virtually every kind of object you can think (including lines). Of course, because Quickdraw 3D was discontinued by Apple years ago, you'd have to use Quesa instead. I used to use 3DMF for all kinds of things, and I can vouch for its usefulness.

I can't think of an editor that would generate just line primitives in 3DMF or any other format, though. Maybe the old QD3D-based modeller 3D World would do the trick, or you could knock one together yourself using Quesa (easier than you might expect).

Are you talking about some kind of Nurbs? Hash uses something called a "patch".

What is it that you want to do? (white lines?? ha ha)

Meshwork has an explicit TRIANGLES section. It doesn't support arbitrary polygons.

You can mark vertices with bones in meshwork... not precisely what you're after, but it might work...