[vtk-developers] [vtkusers] 3D line and coordinate system

[Pengdong Xiao]

Hi Sankhesh and Yumin,

Thank you very much for your suggestions. I will try based on your suggestions. Many thanks again.

Best regards,
Pengdong

> Date: Thu, 10 Jan 2013 13:44:16 -0500
> Subject: Re: [vtkusers] 3D line and coordinate system
> From: yumin.yuan at kitware.com
> To: xiaopd at hotmail.com
> CC: vtkusers at vtk.org; vtk-developers at vtk.org
> 
> Ok, from the email you sent to Sankhesh, I now understand what you try
> to do (and this seems to be similar to the other email thread I just
> replied)
> 
> I think what you need is  vtkPlane::ProjectPoint(...)
>   // Project a point x onto plane defined by origin and normal. The
>   // projected point is returned in xproj. NOTE : normal assumed to
>   // have magnitude 1.
>   static void ProjectPoint(double x[3], double origin[3], double normal[3],
>                            double xproj[3]);
> 
> In your case, do the same for world_coordinate1, then to get the
> second point, you can try
> 
> vtkPlane::ProjectPoint(world_coordinate1, camera->GetFocalPoint(),
> camera->GetViewPlaneNormal(), world_coordinate2);
> 
> HTH,
> Yumin
> 
> On Thu, Jan 10, 2013 at 9:04 AM, Yumin Yuan <yumin.yuan at kitware.com> wrote:
> > Which version of VTK is this?
> >
> > You can try to add the following after setting the two line points.
> >
> > line->Update();
> >
> > Yumin
> >
> > On Thu, Jan 10, 2013 at 3:47 AM, Pengdong Xiao <xiaopd at hotmail.com> wrote:
> >> Hi Yumin,
> >>
> >> Thank you very much for your e-mail. After I change the following:
> >>
> >> display1[2] = 0 ;
> >>
> >> the problem still exists. After I click mouse, a line will be drawn, but it
> >> isn't perpendicular to the screen; and each time the length is different.
> >> Any other suggestions? Many thanks.
> >>
> >> Best regards,
> >> Pengdong
> >>
> >>> Date: Wed, 9 Jan 2013 10:31:29 -0500
> >>> Subject: Re: [vtkusers] 3D line and coordinate system
> >>> From: yumin.yuan at kitware.com
> >>> To: xiaopd at hotmail.com
> >>> CC: vtkusers at vtk.org; vtk-developers at vtk.org
> >>
> >>>
> >>> The VTK display coordinates' z range is 0 to 1, try this:
> >>>
> >>> display1[2] = 0 ;
> >>>
> >>> HTH,
> >>> Yumin
> >>>
> >>> On Mon, Jan 7, 2013 at 9:16 PM, Pengdong Xiao <xiaopd at hotmail.com> wrote:
> >>> > display1[2] = -1 ;
 		 	   		  
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