orbiting a craft around a planet 2004-01-26 - By Thomas Williams
Back
use model.rotate rather than setting transform.rotation
flipping, in my experience, comes from using Euler rotation. Whne one uses
transform.rotation, you are using euler rotation. Node.rotate uses
quaternions (i believe this is the case) and thus avoids flipouts. Flipping
out is usually the dreaded gimbal lock, which results when one attempts to
set rotation on more than one axis. Using Euler transform.rotation, the
rotations cannot be done simulataneously, but must be done sequentially, and
thus it is possible to rotate the node in such a way that one axis lines up
with the other and so when the 3d engine attempts to rotate the next axis,
nothing happens cos the axes are lined up, or locked. btw, a gimbal is a
gyroscope and gimbal lock was first encountered by the apollo missions to
the moon in the 60s.
another possible solution is to use the axisangle. This allows you to avoid
having to use sequencial rotations, as one rotates around a single arbitrary
axis, not an axis based on world or local xyz. This effectively avoids
sequential rotations, but one must determine the axis of rotation to use,
which can be challenging.
hth
Thomas
> -- --Original Message-- --
> From: dir3d-l-bounces@(protected)
> [mailto:dir3d-l-bounces@(protected)]On Behalf Of Allen
> Partridge
> Sent: Monday, January 26, 2004 5:56 PM
> To: dir3d-l@(protected)
> Subject: [Dir3d-l] orbiting a craft around a planet
>
>
> We've been playing around with a new project that involves orbiting a
> craft around a giant sphere -and eventually all sorts of other things
> around that sphere (planet).
>
> We are of course running into all sorts of y flipping to xz problems -
> I'm wondering if anyone has done any substantial work on a project that
> involved objects flying/floating/camera tracking etc. around a sphere.
>
> --thoughts?
>
>
> --al
>
> __ ____ ____ ____ ____ ____ ____ ____ ____ ____
> Dir3d-l mailing list
> Dir3d-l@(protected)
> http://nuttybar.drama.uga.edu/mailman/listinfo/dir3d-l
>
__ ____ ____ ____ ____ ____ ____ ____ ____ ____
Dir3d-l mailing list
Dir3d-l@(protected)
http://nuttybar.drama.uga.edu/mailman/listinfo/dir3d-l
|
|
