Hi all
Appologies to anyone who read the previous misstated query re
objectBehaviour.setRotationCentre() which should of course be
orbitBehaviour.setRotationCenter()
A couple of folk have replied but I detect that I failed to make the issue
clear in the original.
The issue is this.
orbitBehaviour.setRotationCenter(point3d)
correctly updates the OrbitBehaviour to rotate about point3d but spuriously
(outside its stated conract) also shifts the view so that the new center of
rotation appears at the point in the view where the old centre of rotation
used to lie. Its as if it considers your center of rotation to be somehow
your center of interest and is trying to maintain it for you. Some folk may
want that, but its certainly not what either the name or the documentation
describe. SetRotationCentre should just set the rotation center and not
shift the view.
Various folk have raised this as an issue and at one point Andrea Tartaro
[[EMAIL PROTECTED]] back in 04/04/2001 replied to a query to the
group on this topic agreeing that the behaviour was odd and suggesting
xtrans += (rotationCenter.x-center.x);
ytrans += (rotationCenter.y-center.y);
as a fix at the start of the setRotationCenter method.
This does not solve the problem (for me) and I suspect that it may be
something to do with ignoring the Z component of the new point3d
My query was as to whether anyone has managed to get
orbitBehaviour.setRotationCenter() to work without the sputious view shift
by this or any other method.
It has been suggested (Elisabeth Thorson) that this may be a lost precision
problem but I do not believe this as
1) I am working with small coordinates. The maths would have to be very
badly conditioned to have problems at these values in which case it is still
a misfeature and
2) The view shift is always exactly that required to shift the new center of
rotation to the position in the view that the old center of rotation used to
have.
Any help gratefully received
Alex
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