[vtkusers] 3D Slicing | vtkImageResliceMapper | No motion of cutplane in one of 3 axes (yaw)

[David Gobbi]

Hi Debjit,

I've been too busy with work-related projects and haven't been able
to keep up with the VTK lists lately.  If I have time this weekend, I'll
read through the emails that you have sent and prepare a reply.

  David


On Thu, Feb 6, 2014 at 1:34 PM, Debjit Ghosh <dghosh at chla.usc.edu> wrote:
> Hi David,
>
>
>
> It struck me that perhaps by replying on the thread, you aren't receiving
> the emails but I am sending them to myself. Please look at this link where I
> had responded with diagrams to make clear the axes that we were discussing:
>
>
>
> http://vtk.1045678.n5.nabble.com/3D-Slicing-vtkImageResliceMapper-No-motion-of-cutplane-in-one-of-3-axes-yaw-tp5725426p5725433.html
>
>
>
> Warm regards,
>
> Debjit
>
> From: Ghosh, Debjit
> Sent: Wednesday, January 15, 2014 3:12 PM
> To: David Gobbi [via VTK]
>
>
> Subject: Re: 3D Slicing | vtkImageResliceMapper | No motion of cutplane in
> one of 3 axes (yaw)
>
>
>
>
>
> So does this mean that your software has two views, one 3D view and one 2D
> view?  Where the 2D view shows whatever the plane is slicing through in the
> 3D view?
>
>
>
> No it does not. The attached image was to merely show how the system
> functions. There is the 3D volume the software reads, and only the 2D slice
> is rendered on the screen ie. the 2D slice is internally what the cut plane
> slices in the 3D volume.
>
>
>
> Now you have to explain exactly what axis the "yaw" angle rotates around.
> In terms of 3D graphics, a "yaw" generally means rotation around the Y axis
> of the display coordinate system, i.e. around the vertical axis of the
> camera.  Also, whenever you say "x axis", "y axis", or "z axis" make sure
> you are clear about whether you are talking about the axes of the data set
> vs. the axes of the camera vs. the axes of the sensor.  Please don't use
> terms like "yaw out" because I have no idea what that is supposed to mean.
>
>
>
> Knowing the confusion of the usage of axes (sensor, camera or data) is why I
> created a representation of the 3 axes in the attached image and based on
> that roll is in the Y axis, pitch is in Z and yaw is in X.
>
>
>
> Pardon my use of "yaw out". If the plane is centered at the tip of the cone,
> and the plane was to have a yaw motion, it would move like the dial of the
> pendulum from the inside to the outside of the bounding box.
>
>
>
>
>
> On Wed, Jan 15, 2014 at 3:45 PM, Debjit Ghosh <[hidden email]> wrote:
>
> David,
>
>
>
> I definitely understand.
>
>
>
> I have attached an image to this email which depicts what I mean by cut
> plane and what is produced by the positioning of the cut plane. Now, based
> on the axes drawn in the image, Y would be the axis of Roll, Z would be the
> axes of Pitch and X would be the axes of Yaw. Now you can imagine the cut
> plane which is positioned at the tip of the cone to be rolling, pitching and
> yawing.
>
>
>
> Now the orientation of the plane is controlled by a 6DOF sensor. So when the
> sensor rolls, the plane rolls and the image is rendered correspondingly.
> Similar for pitch. Now when the sensor is yawed, the plane remains
> stationary - that's the issue at hand. The plane needs to ideally leave the
> bounds of the box ie. yaw out. As far as pitch is concerned, I have observed
> the plane moves all the way to the top surface of the box.
>
>
>
> Does this make sense?
>
>
>
> From: David Gobbi [via VTK] [mailto:[hidden email][hidden email]]
>
> Sent: Wednesday, January 15, 2014 1:24 PM
> To: Ghosh, Debjit
> Subject: Re: 3D Slicing | vtkImageResliceMapper | No motion of cutplane in
> one of 3 axes (yaw)
>
>
>
> Hi Debjit,
>
> Your question is of the sort that is very difficult to understand without
> some
> sort of visual aid.  Do you have any diagrams that illustrate exactly what
> you want to achieve?  Do you have screenshots to demonstrate what the
> system is doing right now?
>
>   David
>
> On Wed, Jan 15, 2014 at 12:26 PM, Debjit Ghosh <[hidden email]> wrote:
>
>
>> I have been using the vtkImageResliceMapper to slice through a 3D volume
>> using the following logic (thanks to David Gobbi) where I am able to slice
>> in 2 out of 3 axes only. When I change the orientation of the slice in the
>> yaw direction there is no movement of the cut plane. I am not sure what I
>> am
>> doing incorrectly here or whether this is a limitation of the system.
>>
>> Here is the code snippet which implements the slicing using the camera and
>> I
>> wonder if it has to do with the default_norm that I have set to [0,0,1]:
>>
>> matrix_= imageslice->GetMatrix();
>> matrix_->MultiplyPoint(default_viewup, this->view_up);
>>
>> //matrix is a 3x3 rotation matrix which defines the orientation of the
>> cutplane
>> matrix->MultiplyPoint(this->default_norm, this->normal);
>>
>> double focalPt[] = {0,0,0};
>> double centerofvol[] = {dimX/2, dimY/2, dimZ/2}; double origin[] =
>> {dimX/2,
>> dimY/2, 0};
>>
>> vtkSmartPointer<vtkPlane> plane = vtkSmartPointer<vtkPlane>::New();
>> plane->ProjectPoint( centerofvol, focalPt );
>>
>> position[0] = focalPt[0] + distfromcam * this->normal[0]; position[1] =
>> focalPt[1] + distfromcam * this->normal[1]; position[2] = focalPt[2] +
>> distfromcam * this->normal[2];
>>
>> cam->SetPosition(position);             //Orientation of the slice plane
>> cam->SetFocalPoint(focalPt);    //Point at which my plane is fixed
>> cam->SetViewUp(this->view_up);
>> cam->SetWindowCenter(win_center_x, win_center_y);