Displaying objects in all viewports to same scale

Support
1

Screen Shot 2021-11-07 at 5.36.10 PM
Screen Shot 2021-11-07 at 5.36.10 PM598×1200 4.6 KB

I have the same object displayed in two viewports of the render window: bottom is elevation view, top is plan view. My set up is:

  • 1 Hex8 in unstructured grid (box dimensions along X: 1.0, Y: 0.5, Z: 2.0)
  • 1 Actor (mapper, property, etc.)
  • 2 Renderers (1st one has default camera showing XY plane in the bottom viewport, 2nd one has its camera with elevation at 90 deg, showing XZ plane in the top viewport).
  • Viewports have the same physical dimensions.

Q1: What should I do to show these views to the same scale? (since they are two views of the same object)?
Q2: More generally, with different objects in multiple viewports, assuming that the dimension of the objects have the same units, how can they be shown to scale?

Thanks for your help.

2

Got it to work this way:

  • Create an aligned-isotropic-bounding box (vtkOutlineSource) around the object.
  • Create a 2nd vtkActor with a mapper for the BB. Turn visibility off this actor to avoid showing the BB. Add the 2nd actor to both renderers.
  • Set 1st camera’s focal point at the center of the BB, and some distance away. Deep copy to camera 2, and set its elevation at 90 deg.

Don’t know if this is the optimal way to do it.