Re: [Gnu3dkit-dev] 3D file formats

[Brent Gulanowski]

On Thursday, October 3, 2002, at 12:50  PM, Philippe C.D. Robert wrote:

> > I think the NSImageRep cluster is a pretty good model to go with. How 
> > about "G3DSceneRep" instead of "G3DDatabase" to make the model and 
> > purpose clearer?
>
> I thought about it too, but I am not yet convinced, because it is not 
> exactly the same thing. but I am not too religious about this ...:-)

Can you give a set of possible attributes that the G3DDatabase class 
would have? I think of a database as a monolithic interface which 
collects and vends other objects. I don't see how that is like a class 
cluster, unless you mean that the G3DDatabase is vending the scenes and 
scene objects, which might be implemented in any number of ways.

The docs say that NSImageReps are usually managed by the NSImage which 
they are representations of. What would be the analogous object in the 
G3DSceneRep or G3DDatabase design? Images are distinguished by their 
file format and the drawing context; would this be the idea for the 
scene reps?

I have yet to use NSImages much, but here is what I understand. An 
NSImage choses a representation based on where it is asked to draw 
itself.  You can ask it to produce a TIFF representation as NSData, 
which you can then write to disk or convert to another format before 
writing (with Quicktime, say).

If we want to have file format translation support, we would need to 
determine if the G3DDatabase incorporated file format reading and 
writing, or only scene formats for display. The rendering mode might be 
a source of how to "format" a scene for display, if this is a viable 
option.

Would this be a sensible way to provide a more standardized method of 
doing LOD for scenes? I mean, you could create a G3DLODSceneRep for a 
model at different complexity levels, which would then be used 
accordingly. That would replace the G3DLODGroup functionality.

If a G3DGraphNode is a part of a scene, would there be 
G3DSceneGraphSceneRep which held a Scene Tree made of G3DGraphNodes? In 
which case there would be other G3DSceneReps, like say a billboard, or 
a merged scene where all of the nodes had somehow been combined into 
one large Leaf Node?

If the G3DDatabase handled file conversions itself, would we ask it 
for/provide it with) file format specific NSData objects for writing to 
disk/converting into scenereps? It could have convenience methods 
which, given a path or URL and file name, would let us request a file 
be read or written directly into/from a scene object.

Question about v0.3: G3DWorld class was meant to be an absolute root 
nood for a scene graph. Could one have used it as an internal node as 
well? I would like a more general node class which could have world 
attributes but also be used as an internal node, creating a sort of 
sub-world. Perhaps the G3DScene object could do this?

--
Brent Gulanowski                                address@hidden

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