# Anti-aliasing / multi sampling with vtkGenericOpenGLRenderWindow
**URL:** https://discourse.vtk.org/t/anti-aliasing-multi-sampling-with-vtkgenericopenglrenderwindow/2463
**Category:** Support
**Created:** [January 20, 2020, 12:42pm UTC](https://discourse.vtk.org/t/anti-aliasing-multi-sampling-with-vtkgenericopenglrenderwindow/2463 "2020-01-20T12:42:57Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@michael23](https://discourse.vtk.org/u/michael23)
#### Post date: [January 20, 2020, 12:42pm UTC](https://discourse.vtk.org/t/anti-aliasing-multi-sampling-with-vtkgenericopenglrenderwindow/2463/1 "2020-01-20T12:42:57Z")
Hello,
I am using vtkGenericOpenGLRenderWindow and QVTKOpenGLNativeWidget for VTK rendering in Qt.
In order to get the right result when using the vtkSelectVisiblePoints filter, I had to set the number of multi samples to zero:
_vtkGenericOpenGLRenderWindow::SetGlobalMaximumNumberOfMultiSamples(0);_
_QSurfaceFormat::setDefaultFormat(QVTKOpenGLNativeWidget::defaultFormat());_
_auto defaultFormat = QVTKOpenGLNativeWidget::defaultFormat();_
_defaultFormat.setSamples(0);_
_QSurfaceFormat::setDefaultFormat(defaultFormat);_
Unfortunately, without using multi-samples, the quality of the actors is noticeably worse which I would like to avoid.
Can someone explain me why I have to disable multi-samples when using vtkSelectVisiblePoints and vtkGenericOpenGLRenderWindow (vtkRenderWindow does not require it) and if there is any fix for this?
Thank you.
---
### Author:  [@Michael](https://discourse.vtk.org/u/Michael)
#### Post date: [February 18, 2020, 2:22pm UTC](https://discourse.vtk.org/t/anti-aliasing-multi-sampling-with-vtkgenericopenglrenderwindow/2463/2 "2020-02-18T14:22:36Z")
Hi,
The issue has been fixed recently in VTK: [https://gitlab.kitware.com/vtk/vtk/merge\_requests/6356](https://gitlab.kitware.com/vtk/vtk/merge_requests/6356)
You can use the master branch or wait for VTK 9.0 release.