RE: [Plib-devel] Model Formats

[Dave M. <dp...@ef...>]

Steve wrote:
> The AC3D and SSG loaders are not "old" - they work correctly and have
> texture support.

I'm sorry Steve.  Ben asked about "new" model loaders and I just wanted
to categorize the loaders according to age.  The AC3D and SSG loaders
are the oldest and therefore the most stable and tested.

> > I was looking for a list of model formats that ssg can load. At
> one point
> > Steve had mentioned that some new model type where added to the model
> > loading functions but I was unable to find any type of list to say which
> > ones.
>
> So far:
>
>   ASE SSG 3ds DXF TRI AC3D OBJ VRML
>
> Of these, I know that AC3D and SSG work well, I'm not so sure
> about the others because I don't use them much.
>
> Dave:
>
>   Can you comment?
>

The TRI loader was just a quicky I did because it was easy.  It is
the same TRI format that AC3D uses.  I think it comes from Wavefront.

The 3ds loader was created by Per Liedman.  It is a very important
*binary* format.  AFAIK, it works correctly and supports textures.
Per?

The DXF loader was adapted from John Burkardt's IVCON.  With
Wolfram Kuss' help I've updated it to support quads, polylines,
and MxN polymeshes.  It doesn't support textures, which are not
in the DXF specification, but it is a widely supported format
and a good way to import geometry into SSG.

The ASE loader is the one I wrote and use.  I have tested it and
feel confident that it works correctly.  It has texture support.
I'm willing to help anyone use it or improve it.  Any copy of MAX
has the source code for the ASE export plugin.  I'm working on
adding animation support which will require new SSG entities.

The OBJ loader was adapted from John Burkardt's IVCON.  I added
texture support after looking at how Andreas Umbach handled it
in gltron.  The Wavefront OBJ format is wonderfully simple and elegant.

http://www.cica.indiana.edu/graphics/object_specs/OBJ.format.txt

The "Nebula Device" project (http://www.radonlabs.de/) liked the
OBJ format so much they extended it and use the "n3d" extension.
But AFAICT, Wavefront OBJ lacks animation support.  Otherwise,
I would dump ASE and switch over to it.

I hope to cleanup and improve the OBJ loader soon so it can import
the object names and other things I missed the first time.  Also,
the exporter currently lacks texture support.

Many of these loaders have an exporter.  The exporter feature was
mainly needed for PPE (pretty poly editor).  If you want to *save*
a scene graph, you should use ssgSaveSSG() which supports all the
SSG entities.  Otherwise, you'll lose information.

Another *big* todo item is to add ssgIndexArray to the _ssgCreateFunc
so it can support Mark's ssgVertexArray.cxx module.  That would
make large ASE models load and render faster since they are
naturally in indexed array form.

If someone has a specific use for an improved OBJ or ASE loader,
please let me know.  The added motivation always helps.

--Dave McClurg