[vtkusers] Automatically change radius of sphere when a variable changes its value

[M. Jordan]

Thank you! Now it works.

My scene also includes a big polydata object which does not change by time.

Nevertheless, if the object is visible, the time to re-render the scene increases enormously.
So updating the spheres is not the time issue.

Is it possible to only update the spheres and not the polydata object?

________________________________
Von: Ken Martin <ken.martin at kitware.com>
Gesendet: Montag, 07. August 2017 15:16
An: M. Jordan
Cc: vtkusers at vtk.org
Betreff: Re: [vtkusers] Automatically change radius of sphere when a variable changes its value

Position your spheres using the Actor's SetPosition, I am guessing you are changing the spheres' centers in the SphereSource which is the issue.

On Mon, Aug 7, 2017 at 8:30 AM, M. Jordan <mjordan at live.at<mailto:mjordan at live.at>> wrote:

Hello,

i tried to use the ->SetScale() options but it turned out that this changes the position as well.
My goal is to find the fastest way to change the radius of the spheres, without affecting their positions.
Any idea how to solve this issue?

Thank you very much!


________________________________
Von: Ken Martin <ken.martin at kitware.com<mailto:ken.martin at kitware.com>>
Gesendet: Freitag, 04. August 2017 16:28
An: M. Jordan
Cc: vtkusers at vtk.org<mailto:vtkusers at vtk.org>
Betreff: Re: [vtkusers] Automatically change radius of sphere when a variable changes its value

1) actor->SetScale(...) instead of changing the sphere source

or

2) use a Glyph3DMapper with a scale array to control the scale of each sphere

or

3) vtkOpenGLSphereMapper with a scale array

Which solution works best depends on the specifics of your use case, ala is only one sphere changing radius?, are they all?, are they all changing by the same amount? one actor? 100 actors? etc.






On Fri, Aug 4, 2017 at 10:00 AM, M. Jordan <mjordan at live.at<mailto:mjordan at live.at>> wrote:

Hello,

I have a scene with many spheres (about 100) in my QVTK-Widget.
Now I would like to achieve that the radii of the spheres change automatically when a variable changes its value.

Right now I add the spheres to the scene, start a timer and in the timer callback I change the radius of the SphereSources depending on the variable. Finally, I call qvtkwidget->update(); to update the spheres in my scene.

It works, but i would like to improve the speed. Any ideas how to update spheres faster? Is there any possibility to only "re-render" one sphere and not the whole scene?

Thank you!


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--
Ken Martin PhD
Distinguished Engineer
Kitware Inc.
28 Corporate Drive
Clifton Park NY 12065

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--
Ken Martin PhD
Distinguished Engineer
Kitware Inc.
28 Corporate Drive
Clifton Park NY 12065

This communication, including all attachments, contains confidential and legally privileged information, and it is intended only for the use of the addressee.  Access to this email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken in reliance on it is prohibited and may be unlawful. If you received this communication in error please notify us immediately and destroy the original message.  Thank you.
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