Vista - drawing surface, 2D visual surface as plane in the 3D space

Hi,

I am trying to get some information about the visual 2D surface (the
projection plane) in the 3D space and the corresponding projection
(orhtographic, perspective).
Basically I would like to get two vectors which describe this plane. This
seems to be easy because they are orthogonal to the look direction of the
projection camera being used. Is this a correct assumption?
For orthographic projection this might by sufficient to calculate 2D
coresspondents of 3D points because the direction of the projection is normal
to the projection plane (correct assumption?).
In case of perspective projections this seems to be a little bit more
difficult. The projection matrix would be very helpful in this case. Is there
any way to get this matrix or some underlying information to compute this
matrix?
(In the orthographic case it may be M11=1, M22=1, M44=1, 0 otherwise).

Any help concerning this issue is appreciated.
Regards, Ruediger

Yes. There is a sample in my sample (2DLabel) pack at
http://www.therhogue.com/WinFX which finds the 2D point on a 3D object.
Please read the readme.txt for details.

The bad news is that the sample uses a "MatrixCamera". This means a lot of
extra 3D matrix stuff is needed to use this type of Camera.

In V2 of WPF, I think the camera matrix will be exposed, along with a number
of other needed features to make life much easier.

"Ruediger" wrote:

> Hi,
>
> I am trying to get some information about the visual 2D surface (the
> projection plane) in the 3D space and the corresponding projection
> (orhtographic, perspective).
> Basically I would like to get two vectors which describe this plane. This
> seems to be easy because they are orthogonal to the look direction of the
> projection camera being used. Is this a correct assumption?
> For orthographic projection this might by sufficient to calculate 2D
> coresspondents of 3D points because the direction of the projection is normal
> to the projection plane (correct assumption?).
> In case of perspective projections this seems to be a little bit more
> difficult. The projection matrix would be very helpful in this case. Is there
> any way to get this matrix or some underlying information to compute this
> matrix?
> (In the orthographic case it may be M11=1, M22=1, M44=1, 0 otherwise).
>
> Any help concerning this issue is appreciated.
> Regards, Ruediger
>

Thanks,

the 2D label example gave me the necessary hints to solve my problem.

Regards, Ruediger

"TheRHogue" wrote:

> Yes. There is a sample in my sample (2DLabel) pack at
> http://www.therhogue.com/WinFX which finds the 2D point on a 3D object.
> Please read the readme.txt for details.
>
> The bad news is that the sample uses a "MatrixCamera". This means a lot of
> extra 3D matrix stuff is needed to use this type of Camera.
>
> In V2 of WPF, I think the camera matrix will be exposed, along with a number
> of other needed features to make life much easier.
>
> "Ruediger" wrote:
>
> > Hi,
> >
> > I am trying to get some information about the visual 2D surface (the
> > projection plane) in the 3D space and the corresponding projection
> > (orhtographic, perspective).
> > Basically I would like to get two vectors which describe this plane. This
> > seems to be easy because they are orthogonal to the look direction of the
> > projection camera being used. Is this a correct assumption?
> > For orthographic projection this might by sufficient to calculate 2D
> > coresspondents of 3D points because the direction of the projection is normal
> > to the projection plane (correct assumption?).
> > In case of perspective projections this seems to be a little bit more
> > difficult. The projection matrix would be very helpful in this case. Is there
> > any way to get this matrix or some underlying information to compute this
> > matrix?
> > (In the orthographic case it may be M11=1, M22=1, M44=1, 0 otherwise).
> >
> > Any help concerning this issue is appreciated.
> > Regards, Ruediger
> >