i think you can't solve that with vertex shaders since you know nothing about the neighboring geometry there.

this article seems to describe some quake3 specific stuff (i only took a quick glance).

You kbow, i dont think this probem is currenty solvable. The way D3D works precludes smoothing groups or hard edges, unless the vertices are not welded. So basically, its an art thing, not a code or model format thing.

Basically, every shading method uses vertices, not faces, so everything has to be interpolated. Thats why flat shade mode doesnt really work, because it still does shading per-vertex, not per-face.

if you changed the vertex format to include some things, who knows, maybe there is some hack that could work, but frankly ive never seen anything like that. It's a hardware limitation. Maybe with DirectX 10 there will some possiblity.

It could be done in software, but so what, so can anything..

yes, i know that.

but the mesh you work with and the data that gets drawn by direct3d shouldn't and doesn't have to be the same.

i think internally the engine would need a second data structure with a welded closed mesh for calculating stencil shadows (but the a6 stencil shadows are useless anyway ) even if some vertices of the mesh that gets drawn are split to achieve hard edges.

there has to be some solution for this in 3dgs! most other engines have solutions for this.

and the mdl7 format isn't a direct representation of the direct3d mesh. it's an artist format which doesn't only get loaded and displayed by the engine but is also meant to be worked with in med so i don't see a problem with adding some kind of smoothing information to it.

I second that, ventilator.
I have to admit I am no expert in d3d or anything but, seeing that MED can do flat shading while, at the same time, using a directX render library, there certainly has to be a solution to do this same effect in the engine.
Plus, as ventilator stated, other engines -many other engines- support this as well...

I'd really like to hear a word or two from Conitec on this issue.

In the *.X format are smoothing groups available.
If this feature of implementing the *.X format to 3GS is released, than I think it's possible to use smoothing groups with 3DGS.
The Quest3D Engine (www.quest3d.com) can use smoothing groups from *.X format models.

I dont see any way on a API/hardware level that you can have a feature like this. Vertices are either welded in a mesh or not, and I dont believe any modern 3D engine has this kind of feature. With vertex and pixel shaders there is no way to get information from other vertices or to turn off interpolation..

The only method in which this could work is if some sort of light-mapping system was developed specifically for models. Each triangle in MED would get a flag. If the flag is off (default setting), a smooth gradient is used, like that of gouraud shaded mode. If the flag is on, no smoothing is done and is otherwise flat. Smoothing is decent for curved surfaces and flat is decent for flat surfaces that aren't part of a curve. These flags are only used for lightmap calculations for the model. They are ignored in the engine.

I'd still be interested how in heavens MED can do it -with DX, it seems- whereas the engine can't?
That doesn't really make sense to me