[ODE] Re: ODE Digest, Vol 13, Issue 18

Peter twentyseven at urbanterror.net
Tue Sep 14 10:22:05 MST 2004


What are you using to get a bodys rotations?  ode_GetRotation() returns a
3x3 rotation MATRIX, not a set of euler rotation angles, so you'd need to
extract some euler angles from that matrix (which is not really that good an
idea, eulers are bad mmkay) or convert the 3x3 rotation matrix to a
quaternion via dRtoQ().

Cheers.


----- Original Message ----- 
From: <ode-request at q12.org>
To: <ode at q12.org>
Sent: Tuesday, September 14, 2004 6:58 AM
Subject: ODE Digest, Vol 13, Issue 18


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>    1. RE: XYZ Axis Orientation and 0 degrees (Jon Watte)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 13 Sep 2004 11:41:29 -0700
> From: "Jon Watte" <hplus-ode at mindcontrol.org>
> Subject: RE: [ODE] XYZ Axis Orientation and 0 degrees
> To: "Paul Carrington" <paul at vulcan.co.uk>, "Ode at Q12. Org"
> <ode at q12.org>
> Message-ID: <NCEAIDPPLCBOGKGGGHMDGEKEDJAA.hplus-ode at mindcontrol.org>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> 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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> End of ODE Digest, Vol 13, Issue 18
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