From: iain@yoshac.demon.co.uk (Iain W. Barker) Subject: Re: TECH: Orthotropic distances in the Ascension Flock of Bird. Date: 22 Nov 1995 19:12:19 -0000 Message-ID: <48vsmj$1no@yoshac.demon.co.uk> Organization: Private Demon dialup In article <487mt2$61q@hubcap.clemson.edu> you write: >From: stephane morvan > >I was wondering if anyone who is using Ascension's flock of Bird ever >encountered this problem: I placed two trackers with a known distance >between them, and I computed the distance measured via the interface >we have with the HMD. Then I swivel the system of 90 deg. and the >distance became half its value, just like if the Magnetic field was >compressed, or shrinked in the direction. Just an idea: Does your lab area use overhead fluorescent lighting? If it does, you'll probably find that they are arranged in parallel strips. In this case the ballast coils will all be aligned and producing a directional field which will be aligned with your tracker in one orientation, and at 90 degrees when you set up the system the other way. The coils should be screened, but you never know... Iain -- Iain Barker, Maidenhead, UK. .-. .-. .-..-. .-..-. .-..-. Home: iain@yoshac.demon.co.uk | |__ | | | .` | | || | > < Work: ibarker@bnr.ca `----' `-' `-'`-' `----' '-'`-` Tel: +44 (0)1628 826518 Life is too short to compute on anything else