Re: ANNOUNCE: Plsase test my VRML Tube Ride

Christopher Fouts (fouts@gameover.atlanta.sgi.com)
Mon, 11 Dec 1995 09:59:59 -0500


On Dec 8, 9:33pm, Bryan J. Smith wrote:
> Subject: Re: ANNOUNCE: Plsase test my VRML Tube Ride
) Thanks for your help, I'm using Fountain and it set the values for
point
) lights at 1.3. I fried your cornea, sorry, by going to 100. I hope
I
) didn't pop your Indy's pixels.

Only a couple fell out, and I was able to stick them back in.

) However, I tested with Webspace 1.0 for Win and it seems as if I
) have an object axis problem that does not occur in WebFX. Rather
than
) going into the wave I go up and down when pushing on the control
stalk.
) Pushing on the arrow pad will take you in but this is not the right
) control to use.

That's because the walk viewer in Webspace expects the up vector to be
+Y and your tube seems to be modeled with +Z as the up vector. I seem
to recall that it is specified somewhere in the spec (or maybe its just
folklore) that +Y is the preferred up direction. Ah, here it is. From
the VRML 1.0 spec at http://vrml.wired.com/vrml.tech/vrml10-3.html:

"Coordinate System:
VRML uses a cartesian, right-handed, 3-dimensional coordinate
system. By default, objects are projected onto a 2-dimensional
device by projecting them in the direction of the positive Z
axis, with the positive X axis to the right and the positive Y
axis up. A camera or modeling transformation may be used to
alter this default projection."

It would be nice, however, if our walk viewer was a bit more flexible.
Perhaps with the 1.1/2.0 spec, the appropriate information will be in
the VRML file to allow this (ie, the world up vector).

-- 

Chris Fouts, SGI, Atlanta, GA -- Email: fouts@atlanta.sgi.com Vmail: 5-8714 -- Fone: (770)-475-0464 -- Phax: (770)-475-4414

"The way this day has gone, I'm surprised I remembered to put on my pants this morning. Oh gesat, how long has my fly been open?"


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