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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Here, I typed this quickly to demonstrate. Adding a cone and cylinder, cylinder will be fixed in 3D space, and cone will be always facing the camera. Attached
some shots on what it looks like.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">HTH,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Miro<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">#include <vtkFollower.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">#include <vtkPolyDataMapper.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">#include <vtkRenderWindow.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">#include <vtkRenderer.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">#include <vtkRenderWindowInteractor.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">#include <vtkConeSource.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">#include <vtkCylinderSource.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">#include <vtkSmartPointer.h><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">#define VTK_CREATE(type, name) vtkSmartPointer<type> name = vtkSmartPointer<type>::New();<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">int main()<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">{<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> VTK_CREATE(vtkRenderWindow, rw);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> VTK_CREATE(vtkRenderer, ren);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> rw->AddRenderer(ren);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> VTK_CREATE(vtkConeSource, cone);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> VTK_CREATE(vtkPolyDataMapper, coneMapper);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> coneMapper->SetInputConnection(cone->GetOutputPort());<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> VTK_CREATE(vtkFollower, coneFollower);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> coneFollower->SetMapper(coneMapper);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> // tilt the cone a bit so that we can see its orientation better<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> coneFollower->RotateY(40);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> coneFollower->SetPosition(0, 3, 0);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> coneFollower->SetCamera(ren->GetActiveCamera());<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> ren->AddViewProp(coneFollower);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> VTK_CREATE(vtkCylinderSource, cylinder);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> VTK_CREATE(vtkPolyDataMapper, cylinderMapper);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> cylinderMapper->SetInputConnection(cylinder->GetOutputPort());<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> VTK_CREATE(vtkActor, cylinderActor);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> cylinderActor->SetMapper(cylinderMapper);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> ren->AddViewProp(cylinderActor);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> VTK_CREATE(vtkRenderWindowInteractor, iren);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> rw->SetInteractor(iren);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> ren->ResetCamera();<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> rw->Render();<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> iren->Start();<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> return 0;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">}<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Richard Frank [mailto:rickfrank@me.com]
<br>
<b>Sent:</b> Friday, March 25, 2016 6:30 PM<br>
<b>To:</b> Miroslav Drahos <mdrahos@aurisrobotics.com><br>
<b>Cc:</b> vtkusers@vtk.org<br>
<b>Subject:</b> Re: [vtkusers] camera follower in 3D<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Ok, I could never get it to work. But more specifically, I need the box/clip widget to stay perp to the camera. It is composed of many actors( which are private)<br>
<br>
Rick Frank<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
On Mar 25, 2016, at 9:19 PM, Miroslav Drahos <<a href="mailto:mdrahos@aurisrobotics.com">mdrahos@aurisrobotics.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Rick,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">There is no such restriction for vtkFollower. It is a vtkActor, so can be used with a variety of different data sources, such as polydata. That’s the case for
example with the oriented polygonal handle representation. </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">The transform that you are looking for is calculated in vtkFollower::ComputeMatrix().</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Cheers,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Miro</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Richard Frank [</span><a href="mailto:rickfrank@me.com"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">mailto:rickfrank@me.com</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">]
<br>
<b>Sent:</b> Friday, March 25, 2016 5:57 PM<br>
<b>To:</b> Miroslav Drahos <</span><a href="mailto:mdrahos@aurisrobotics.com"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">mdrahos@aurisrobotics.com</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">><br>
<b>Cc:</b> </span><a href="mailto:vtkusers@vtk.org"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">vtkusers@vtk.org</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><br>
<b>Subject:</b> Re: [vtkusers] camera follower in 3D</span><o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Thanks the problem I've had with VTK follower is that it seems dedicated to text- it puts text at the viewport z= 0 and doesn't seem to work for something at the camera focal point<br>
<br>
Rick Frank<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
On Mar 25, 2016, at 7:49 PM, Miroslav Drahos <<a href="mailto:mdrahos@aurisrobotics.com">mdrahos@aurisrobotics.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">It uses vtkFollower (a subclass of vtkActor that always faces the camera). So make sure to check out vtkFollower as well.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Miro</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Miroslav Drahos
<br>
<b>Sent:</b> Friday, March 25, 2016 4:45 PM<br>
<b>To:</b> 'Richard Frank' <</span><a href="mailto:rickfrank@me.com"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">rickfrank@me.com</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">>;
</span><a href="mailto:vtkusers@vtk.org"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">vtkusers@vtk.org</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><br>
<b>Subject:</b> RE: [vtkusers] camera follower in 3D</span><o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Rick,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Look at vtkOrientedPolygonalHandleRepresentation3D
</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><a href="http://www.vtk.org/doc/nightly/html/classvtkOrientedPolygonalHandleRepresentation3D.html"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">http://www.vtk.org/doc/nightly/html/classvtkOrientedPolygonalHandleRepresentation3D.html</span></a><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">It does exactly that – keeps the widget rep (polydata) in a fixed orientation with respect to camera.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">HTH,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Miro</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> vtkusers [</span><a href="mailto:vtkusers-bounces@vtk.org"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">mailto:vtkusers-bounces@vtk.org</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">]
<b>On Behalf Of </b>Richard Frank<br>
<b>Sent:</b> Friday, March 25, 2016 4:41 PM<br>
<b>To:</b> </span><a href="mailto:vtkusers@vtk.org"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">vtkusers@vtk.org</span></a><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><br>
<b>Subject:</b> [vtkusers] camera follower in 3D</span><o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Hi,<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Has anyone successfully created a widget or other object that stays facing the camera in 3D?<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">I've been trying to get the boxwidget to stay with one side facing the camera and I've come close - by computing a change of basis matrix after computing the camera position, direction of projection, etc. and creating a rotation matrix
from the basis column vectors.<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">When I have the PlusX face of the box widget facing the camera, and move the camera with the trackball interactor, the face of the widget stays facing (seems like it is standing still) but the size/scale of the box gets smaller as I rotate
by sliding the mouse from right to left. <o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">It seems that I need to compensate for some scaling of the rotation matrix but I'm not sure exactly what. I'm putting together a small example if someone wants to take a look at it.<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Thanks<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Rick<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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