Co-Ord ( was ElevationGrid II )

[Neil Woodhouse <N.Woodhouse@earth.leeds.ac.uk>]

Hi everybody,


In view of this and comments made by others may i propose that we make a move to get this implemented.

Neil



Neil Woodhouse wrote:
> In Rikk & Gavins book Annotated VRML 2.0 there is a mention of
> CartesianCoordinate3float, with the words " might possibly be
> added in the future."  What's happening with this and what
> is it's intended content.

The complete text (which I just cut&pasted from the online book at
http://www.wasabisoft.com/Book/) is:

"The VRML 1.0 term for the Coordinate node is Coordinate3. The "3" was
originally added in case support for 2D coordinates was added. It was
dropped because the VRML 2.0 naming philosophy is to give each node the
most obvious name and not try to predict how the specification will
cchange in the future. If carried out to its logical extreme, then a
philosophy of planning for future extensions might give Coordinate the
name CartesianCoordinate3Float, since support for polar or spherical
coordinates might possibly be added in the future, as might
double-precision or integer coordinates."

I guess I should have added:

"CartesianCoordinate3Float might be a logical name, but Coordinate is much
more concise, and was chosen because even if other types of coordinates
are specified in the future, the name 'Coordinate' can still be used for
the most common case."

So far, there has been talk about adding:
  -- Two-dimensional coordinates (Coordinate2 maybe?) for two-dimensional
shapes/figures.  I believe the MPEG-4 working group will be looking at the
MPEG-4 committee's extensions (I haven't looked at their proposal, but
would guess they have some type of 2D coordinate node for their 2D shape
extensions).

  -- Double-precision coordinates (DoubleCoordinate maybe?) to support CAD
applications that require very-high-precision models.  I'm suprised a
VRML-For-CAD working group hasn't started to talk about this, and about
adding trimmed NURBS and other features common to CAD applications.

Since you posted to the geovrml newsgroup, I assume you're interested in
spherical coordinate systems that would be more appropriate for
representing geographical features.  I haven't heard of anybody proposing
or implementing such extensions (SphericCoordinate maybe?).

-- 
Gavin Bell (gavin@wasabisoft.com)
SkyPaint: what do QuickTimeVR, 3DStudio and VRML have in common?
  http://www.wasabisoft.com/