[vtkusers] vtkImageActor erases other actors?

[Andreas Pedroni]

Dear list

I would like to display a 3D object in front of a vtkImageActor (using Python 3.6 and vtk on Mac OS, see code below). However, the vtkImageActor erases the 3D object. I read in the manual that one should use AddProp() with the renderer to add a vtkImageActor to a render scene. But there is no AddProp() method for the renderer class. I’d be very thankful for any suggestions. 

Best 
Andreas 


import vtk
import cv2
from vtk.util import numpy_support

IMAGEPATH = ‚/models3d/'
VIDEOPATH = "20180816-133303.mp4“

def main():
   cap = cv2.VideoCapture(VIDEOPATH)
   success, frame = cap.read()

   frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
   vtk_array = numpy_support.numpy_to_vtk(frame.reshape((-1, 3), order='F'), deep=False)

   # Create a vtkImage Object. This is filled with the vtkArray data later
   vtk_image = vtk.vtkImageData()
   vtk_image.SetDimensions(720, 1280, 1)
   vtk_image.SetSpacing(720, 1280, 1)
   vtk_image.SetOrigin(720, 1280, 0)
   vtk_image.GetPointData().SetScalars(vtk_array)
   # create the Texture for a plane

   # The Screen where the movie is mapped onto
   plane = vtk.vtkPlaneSource()

   plane_mapper = vtk.vtkPolyDataMapper()
   plane_mapper.SetInputConnection(plane.GetOutputPort())

   plane_actor = vtk.vtkImageActor()
   plane_actor.SetInputData(vtk_image)
   plane_actor.SetScale(1, 0.5625, 1)
   plane_actor.SetOrientation(180, 180, 90)

   # add the spine object
   obj_importer = vtk.vtkOBJReader()
   obj_importer.SetFileName(IMAGEPATH + 'Spine.obj')
   obj_importer.Update()

   spine_mapper = vtk.vtkPolyDataMapper()
   spine_mapper.SetInputConnection(obj_importer.GetOutputPort())

   spine_actor = vtk.vtkActor()
   spine_actor.SetMapper(spine_mapper)
   spine_actor.SetOrientation(90, 10, 90)
   spine_actor.SetScale(0.3, 0.3, 0.3)

   # set up the renderer and the window
   ren = vtk.vtkRenderer()
   ren_win = vtk.vtkRenderWindow()
   ren_win.AddRenderer(ren)
   ren_win.SetSize(1500, 1500)

   ren.AddActor(spine_actor)
   ren.AddActor(plane_actor)

   ren.SetBackground(0, 0, 0.1)

   iren = vtk.vtkRenderWindowInteractor()
   iren.SetRenderWindow(ren_win)

   # Initialize must be called prior to creating timer events.
   iren.Initialize()

   # start the interaction and timer
   iren.Start()

if __name__ == '__main__':
   main()