Re: [open_cad_format] x3d format

[Lars O. Grobe]

> I might say a silly thing, but is not x3d aimed at being an open 3D
> cad format?
> Its primary goal is to replace the vrml, but it is also an eXtensible
> 3D format, which should let some place for freedom, shouldn't it?
>
Not a silly thing, but now, x3d is not a CAD format. It stores 3d
geometry among other things, but it aims not at editing but at
describing "worlds" (which include things like behaviour, network
functionality, sound not typically needed in CAD). So an x3d interface
is a great thing to have in any 3d application, but the CAD database
that is used to keep the model in the design and editing process would
be different then the model to display and explore. You COULD add the
missing features to x3d creating a different profile, but I think the
CAD model and x3d have so little in common that this would only obscure
the format. One basic example why the formats have to be different: take
a geometry that is creating by cutting a hole into a wall. In CAD, you
would do everything to preserve the information of the wall and the hole
as seperate objects and perform the "bool" operations as late as
possible to make it possible to edit the objects later. In x3d you would
store the result of the operation - for file size (transported over the
network) and performance (no need to compute everything again and again)
reasons. Sure that others are much better in explaining the differences,
but this in one easy to understand...

CU Lars.