Re: Some questions: OpenGL and free 3D models

["Keith Lucas" <klucas@atlan-tech.com>]

>Sorry, normal-x, normal-y, normal-z - the surface normal at
>that vertex.  If you need a hard edge in your model (one
>that isn't smoothed over) then you need different normals
>on the two polygons...hence they are 'different' points and
>can't share.

Of course.. yeah. Ah. Hmm. Oh. I'd forgotten about that. Yeah. Hmm
Actually I need hard edges in some of the models as well. Hmm. See what
you mean about 12D stuff. That's not a bad way of doing it. I can see the
pre-processor that wanders over the model to get it into a renderable
state is going to have to be quite smart. It's a shame you can't
specify sets of indicies for texture look-ups and so on.
Transforming extra verticies will add to the GL loading a bit.

It's not even as simple as some objects need smoothing and some don't -
the tanks have canvas parts and the soldiers are carrying weapons...

How easy is to specify faceted stuff in modelling packages? In fact, if
I'm going to get a "proper" package what would people recommend, given that
a) I'm not that hot an artist so it won't get that much use and b) cheaper and
less featureful would be better than expensive. Oh and c) I'm after design
capabilities rather than actual rendering ability.



Actually I
know the vertexes will share a colour because I've got no effects
to put on using that as far as I know. So I was just going to leave
it a neutral grey until I think of something to do with it or just
use straight texturing and not use vertex colours at all.

Although I did ponder using an underlying colour to show battle damage -
the issue then is storing and updating a colour for each vertex for the
model for each object. But it would be quite neat - that way the troops
get individual bloodstains and the tanks get blackened patches from impacts...
but at current machine levels that's just not possible to do for N-thousand
objects.

To be honest, I'd rather have more objects than lighting effects and
other stuff like that. Since it's not really a FP perspective they
probably won't show up anyway.

> I'm having enough of a headache dealing with all the
> objects having 4D positions specified...

>You are using glVertex4 calls?  You hardly ever need to
>do that in practice - what makes you think you care about
>the 4th component?

Ah, no, the physics modelling system uses 4D co-ordinates because we model time
continously,
so we can have neat little evaluators that run predictive stuff. Not at the
OpenGL level.