[ODE] XYZ Axis Orientation and 0 degrees

[Jon Watte]

There is no "up". There is no "identity orientation" per se. They 
all are just what you want them to be. ODE isn't even sensitive to 
left- or right-handedness (except in the triangle mesh description 
winding order). Just plug in the numbers you expect, and interpret 
them in the same, consistent, manner, and you'll get out what you 
want.

There are some minor niggles, such as certain geoms are created 
in a specific "major axis" only (ccylinder, I think?) that you may 
have to adjust with a GeomTransform, but there's no consistent, 
single convention used or enforced.

If you want Y up, then make gravity be <0,-9.8,0>.

If you want (0,0,0) to mean "points along +X" then just make sure 
that your objects are created with their major direction being 
along +X (and your camera starts out looking along +X).

Cheers,

			/ h+


-----Original Message-----
From: ode-bounces at q12.org [mailto:ode-bounces at q12.org]On Behalf Of Paul
Carrington
Sent: Monday, September 13, 2004 10:28 AM
To: ode at q12.org
Subject: [ODE] XYZ Axis Orientation and 0 degrees


I'm new to ODE and I'm hoping someone can help me understand ODE's XYZ
Axis orientation and direction of 0 degrees

Studying some of the samples I see that Z is used as the UP vector

I was hoping to ...

1) pass (x,y,z) euler angles from my own graphics engine into ODE 
2) after setting the objects position and rotation, let ODE do it's amazing stuff
3) pluck the ODE object's (x,y,z) euler angles back into my graphics engine

..position works no problem (as long as I swap the up axis's) but something is
going very wrong with the euler angles on the x,y,z axis's

To help explain, here is a 'jpg link' that shows how my engine uses the x, y, and z
axis's and where 0 degrees begins

http://www.vulcan.co.uk/artwork/xyz.jpg

Can someone provide me with a similar graphic image that explains how ODE
treats the x,y and z axis's (or an explanation) :)

thanks
Paul Carrington
Vulcan Software Ltd.
http://www.vulcan.co.uk
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