Re: Performer problem
knut (giraffe.asd.sgi.com!sgi.sgi.com!relay.sgi.com!eurohub.neu.sgi.com!oslo.sgi.com!kknut)
Fri, 7 Jan 1994 09:31:46 +0000
>
> Hi
>
> Perhaps someone could help me with this
>
> There follows a description of my problem.
>
> I am using a Polhemus device, giving me xyz and azimuth,
> elevation, and roll, to navigate around a virtual space.
> I use the xyz as input to the pfChanView function, to set my
> viewer position, and then use the azimuth elevation and roll (azr)
> as input to pfChanViewOffsets, to supply me with viewer orientation.
> I have a simple test object, which is a rectangular 3d object, with the top
> coloured blue, the front green, and the rest white. The colour coding is to
> ensure that I have a reference for navigation in the virtual world. So, a
>typical test I
> have done is to rotate the tracker around the x axis, which gives me my object
> rotating the other way (as you might expect), with rotation going through all
360 degrees,
> as I would have expected. Now, I decided to use the Performer earth sky
model. I
> find that it has several funny effects. First, it seems to rotate at about
twice
> the rate as the viewpoint (as referenced by my reference 3D object).
Secondly, it seems
> to sometimes swallow the 3D objects (the object sinks into the ground).
> Now, as I have not defined the 3D objects as a DCS, it must therefore be
static (and not moving),
> so this means the ground moves !
>
> Clearly something is wrong here. It could well be some aspect of Performer I
do not understand.
> Are there any known problems with the earth sky model ? I have an Onyx system
with VTX graphics,
> in case that is relavent. I have spent two days
> trying to figure out if it is something I am doing wrong, so
> thanks in advance for any help you can give.
>
> If the above is in any way unclear then please get back to me for
clarification.
>
> Thanks
> Richard Gallery
> Philips Research Labs
> Redhill
> Surrey
This archive was generated by hypermail 2.0b2
on Mon Aug 10 1998 - 17:50:08 PDT