Hi Hans,
I don't know how to construct a locale with origin at Origine(x,y,z) ,can you tell me
how?
Mohammed
Hans RAKOTOMANGA schrieb:
> The rotation/orbiting about a Center ( x, y, z ) seems to be the best solution for
>you, however
> if you absolutely use the default behavior, wouldn't it be possible to create a new
>locale at the
> coordinates mentioned and attach the viewplatform to that locale ? We should be able
>to see
> the objects in the other coordinate system.
>
> my two pence.
>
> Hans
>
> ______________________________ Reply Separator _________________________________
>
> [EMAIL PROTECTED]
> 25/10/2000 10:44:00
>
> To: [EMAIL PROTECTED]@internet
> cc: (bcc: Hans RAKOTOMANGA/ress/fr/socgen)
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> Importance: Normal
>
> SUBJECT: Re: [JAVA3D] Rotation Matrix
>
> Hi Mohammed!
>
> It is esier then you describe.
> The A matrix is actually constant. The center of the object should be
> calculated only once, when the object is just created , and no
> transformation is aplied to
> it yet.
> All further transformations are present in T matrix, so what this formula
> does is first return the object to it creation place (T^(-1)) move it from
> its creation place
> to the origin (A^(-1)) then rotate the object (R), then move it back to
> objects creation place (A), and apply the objects transformation (T). This
> complex operation, performed as single matrix multiplication will result
> in object rotation in place. The same technique will zoom the object in
> place if instead of R matrix you will use S matrix that scales the object
> .
>
> Boris.
>
> On Tue, 24 Oct 2000, Mohammed Akacem wrote:
>
> > Hi Boris,
> > I unterstand now what you mean.
> > to get the A matrix I can use the BoundingBoxcenter Ok , but when the user
>translate
> > the object again I would have to get the new Center and to calculate the new A
>matrix
> > again(I am using the MouseRotate, MouseTranslate and MouseZoom classes)I think it
> > would be complicated to keep track of the Center coordinate since it is being
>changed
> > at different places I would then need a sort of globale variable don't you think
>so?
> >
> > Mohammed
> >
> > Epelman Boris schrieb:
> >
> > > Hi Mohammed!
> > >
> > > I do not think that what you are sying is possible,
> > > but the way I suggested you need to calculte the matrix
> > >
> > > T*A*R*A^(-1)*T^(-1)
> > >
> > > first and then multiply the transform attached to your object by this
> > > matrix as a single operation. In that way you perform only one
> > > multiplication
> > > by the matrix, thing that you anyway want to do if you are rotating the
> > > object.
> > > Hope it helps,
> > >
> > > Boris Epelman
> > >
> > > On Tue, 24 Oct 2000, Mohammed Akacem wrote:
> > >
> > > > Hi Boris,
> > > >
> > > > my point is that I don't want to translate the object to the origine because my
> > > > objects kann have 500.000 triangles or more( and that will cost me too much
> > > > time). Until now I have translated my objects to the origine and it works fine(
> > > > andthat is done with the A Matrix you suggest I should use). What I was
> > > > thinking about is(I don't know if this is possible) to translate the coordinate
> > > > origin to the center of the boundingbox und rotate my objects(using the
> > > > MouseRoate behavior).
> > > >
> > > > Mohammed
> > > >
> > > > Epelman Boris schrieb:
> > > >
> > > > > Hi!
> > > > >
> > > > > You need to perform the following transformation:
> > > > >
> > > > > T*A*R*A^(-1)*T^(-1)*M
> > > > > where
> > > > >
> > > > > M is your object
> > > > > T is the object's transform that holds all bthe transformations performed
> > > > > on the object tillnow.
> > > > > A this matrix brings the center of the object to (0,0,0) if the object was
> > > > > not originally created at the origin.
> > > > > R your rotation matrix
> > > > >
> > >> > Tell me if it helped.
> > > > >
> > > > > Boris
> > > > >
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