The meaning of azimuth, elevation etc. is indeed same with VTK and ParaVIew. ParaView uses the same code for Camera as in VTK, so there's no different there. Here's some explanation on the inner workings of the camera:
+ The camera->ViewUp is used by vtkCamera as a "hint" for the up direction. Thus, it is need not always be orthogonal to the view direction (defined by camera position and camera focal point). Unless the ViewUp is parallel to the view -direction, the vtkCamera will automatically compute the true "viewup" internally using vtkCamera::ViewUp as a hint. + You can use cam.OrthogonalizeViewUp() to force the vtkCamera to update the VIewUp based on the internally used ViewUp. e.g. >>> cam = GetActiveCamera() >>> cam.SetPosition(0, 3, 3) >>> Render() >>> cam.GetViewUp() (0.0, 1.0, 0.0) >>> cam.OrthogonalizeViewUp() >>> cam.GetViewUp() (0.0, 0.7071067811865476, -0.7071067811865476) I am not sure I observe the same problem as you mention with Azimuth/Roll. Utkarsh On Mon, Oct 6, 2014 at 8:25 PM, Kazuyoshi Furutaka <[email protected]> wrote: > Could someone tell me whether the meanings of the azimuth and > the elevation in ParaView the same as those in VTK (or "The > Visualization Toolkit" book, 4th ed.) or not? > > In the book it reads: > "Changing the \textit{azimuth} of a camera rotates its position > around its view up vector, centered at the focal point. Think > of this as moving the cmaera to the left or right while always > keeping the distance to the focal point constant. Changing a > camera's \textit{elevation} rotates its position around the cross > product of its direction of projection and view up centered at the > focal point. This corresponds to moving the camera up and down. > To \textit{roll} the camera, we rotate the view up vector about > the view plane normal. Roll is sometimes called twist." > > I sometimes observe that (in the Multi Slice view,) Azimuth() > "rolls" instead of moving the camera left/right. > > That's why I want to understand the geometry of view-up, direction > of projection, and so on... > > Kazuyoshi > > > From: Kazuyoshi Furutaka <[email protected]> > Subject: Re: [Paraview] Is the VIEW-UP vector updated automatically? > Date: Tue, 07 Oct 2014 08:57:30 +0900 (JST) > >> I just want to write a Python macro to change/rotate the camera >> position using Azimuth() and Elevation(). >> >> In addition to the following: >> >>> I'm observing a curious behavior of paraview.simple.Azimuth(); >>> camera is NOT moving left/right. >> >> I sometimes get the following message >> >> Warning: In >> /home/furutaka/work/ParaView/ParaView.git/VTK/Rendering/Core/vtkRenderer.cxx, >> line 1030 >> vtkOpenGLRenderer (0xa702510): Resetting view-up since view plane normal is >> parallel >> >> and am wondering how can the view-up be parallel to the view-plane >> normal... >> >> My understanding is that the view-up is (always) perpendicular to >> the direction of projection (pointing upward of the computer display) >> and therefore parallel to the view-plane, so the view-up should always >> be normal to view-plane normal. >> Isn't the view-plane normal parallel to the direction of projection? >> Isn't the view-plane parallel to the front/back clipping planes? > -- > Kazuyoshi Furutaka > furutaka _dot_ kazuyoshi _at_ jaea _dot_ go _dot_ jp > _______________________________________________ > Powered by www.kitware.com > > Visit other Kitware open-source projects at > http://www.kitware.com/opensource/opensource.html > > Please keep messages on-topic and check the ParaView Wiki at: > http://paraview.org/Wiki/ParaView > > Follow this link to subscribe/unsubscribe: > http://public.kitware.com/mailman/listinfo/paraview _______________________________________________ Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the ParaView Wiki at: http://paraview.org/Wiki/ParaView Follow this link to subscribe/unsubscribe: http://public.kitware.com/mailman/listinfo/paraview
