Hello,
I am trying to extract polydata attributes and save them in 2D images. In other words, take an input mesh and generate renderings from different view points.
I use the vtkCellLocator to find intersections using a finite segment starting from a 2D plane. When an intersection is found, I extract the Normal vector and the distance from the 2D plane (Z Buffer).
Here is the result:
The problem starts when the vtkCellLocator does not locate the correct intersection/cell (see incorrect coloring of the resulting image). I have tried subdividing the surface using ALL the available subdivision filters to improve the vtkCellLocator but it does not work consistently or the surface degenerates.
Here is an example of a degenerated surface.
My question is, is there a better way to achieve this goal? Extract polydata attributes from a view point and save them as 2D images?
Here are some screenshots using ShapePopulationViewer and coloring by direction. I was expecting to have similar results but it is not the case.
Any comment or feedback is greatly appreciated.
Thanks
Following this example using shaders ColorByNormal
combined with the windowToImageFilter I am able to achieve extracting images/screenshots from different viewpoints.
The program works well in a MACOS environment but not in Linux el7.x86_64.
I’m using VTK-9.0. Are there any special options I should be using when compiling VTK in Linux?
How can I make this program work offscreen?
I tried setting vtkRenderWindow::OffScreenRenderingOn() but access the XServer is still needed when executed (I get segfault when running it remotely without ssh -XY option).
When using option -XY I get the following error (the problem is not XServer as I am able to execute other applications)
X Error of failed request: BadValue (integer parameter out of range for operation)
Major opcode of failed request: 149 (GLX)
Minor opcode of failed request: 3 (X_GLXCreateContext)
Value in failed request: 0x0
Serial number of failed request: 52
Current serial number in output stream: 53
When compiling VTK I tried setting the option ‘VTK_USE_X’ to OFF. The error is the same as above.
Another option was to use ‘VTK_OPENGL_HAS_OSMESA’ to ON but this gives the following error.
CMake Error at CMake/vtkModule.cmake:4145 (message):
Could not find the OSMesa external dependency.
Call Stack (most recent call first):
CMake/vtkModule.cmake:4695 (vtk_module_find_package)
Utilities/OpenGL/CMakeLists.txt:49 (vtk_module_third_party_external)
Please help.
Best,
Solution:
Compile with VTK_USE_X=OFF VTK_OPENGL_HAS_EGL=ON
instead of generic vtkRenderWindow use vtkEGLRenderWindow
