[ODE] XODE - should angles be in degrees or radians?

[Bob Dowland]

Hi guys,

I'm not a fully fledged ODE user, so no vote. However, I do work on (game) cd and physics and until Adam's last post I was beginning to wonder how this could even be a point of discussion. I mean, angles are measured in radians, degrees are for decorating protractors, right? ;)

But, not being able to store things like right angles precisely, would seem like a bit of a showstopper for a geom/phys file format. To my mind this completely rules out radians because of the factor of pi in any of the common angles. This leaves: multiples of full circle (ie multiples of 2pi); multiples of pi (ie radians you can write down); and of course good 'ole degrees.

Perhaps degrees have the edge here given that so many of us have protractors. Although, on a more general note, while human-readability is good (especially in a human-readable file), in the words of the whispy-haired gentlemen,

"A theory should be as simple as possible... and no simpler."

Bob.


> -----Original Message-----
> From: Chris Ledwith [mailto:cledwith at d-a-s.com]
> Sent: 19 March 2004 14:49
> To: ode at q12.org
> Subject: Re: [ODE] XODE - should angles be in degrees or radians?
> 
> 
> >> I lean towards degrees.  Now, hear me out. :)  Radians are great,
> >> everyone loves radians, the maths libs use radians, ODE uses
> >> radians.  End of story?  Well, not really; remember that when these
> >> numbers hit the XML file they'll be stored as decimal (that's not
> >> a certainty, but using, say, base PI isn't going to help make
> >> the format intuitive!).  The common angles of 90 degrees, 180
> >> degrees, 120 degrees etc look like hell in a text form as
> >> radians, and are also doomed to lose accuracy as they're
> >> dumped/undumped from a textual decimal representation.
> >>
> >> Just food for thought...
> >>
> >> --Adam
> 
> Good point. Perhaps degrees are better...
> 
> > Maybe using multiples of PI isn't such a bad idea, it 
> solves the precision
> > issue but not the intuitivity/humanreadability one. (but, 
> '0.5' for a
> > '90' degree angle is still more readable than
> > 1.5707....................................... *add arbitrary PI
> > precision here*)
> >
> > Wladimir
> >
> 
> Putting it in "units of PI" would still require a conversion 
> so if you're
> going to require a conversion then it'd be better to just go 
> with degrees.
> In most cases there will be "30", "45" or some such so it should be
> obvious enough that these are degrees and not radians.
> 
> -Chris
> 
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> 

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