First noticed and described in this comment I have asked AI to provide a test script that can replicate the behavior I’m seeing in my larger application. Here’s the prompt I gave claude.ai for completeness:
I’m looking for a standalone python VTK script that has the following setup. There is one VTK assembly which contains a 1-unit sized cube (vtkActor) as well as a vtkAxesActor located at that cube’s origin. The assembly is moved to the world position (100, 100, 100) and the camera has it’s focal point on that location. I want the vtkAxesActor to be hidden initially, but when the user presses ‘a’ it reduces opacity of the cube and makes the vtkAxesActor visible. Pressing ‘a’ reverses the process, turning the axes visibility off and the cube back to normal opacity. I want to print the following information in screen coordinates: the renderer/camera GetClippingRange(), the bounding box for the vtk assembly, the bounding box for the cube actor, and the bounding box for the vtkAxesActor.
The script runs and provides what I need
test.py (5.1 KB)
Here’s what it looks like before and after turning on the axes with the ‘a’ key:
Notice the value of “Axes Actor Bounding Box” and how it affects the “Assembly Bounding Box” and “Camera Clipping Range” when it’s visible - the clipping range changes from (2.464, 6.357) to (0.359, 359.204) . I assume this is because of the determination of the top-level bounding box when self.renderer.ResetCameraClippingRange() is run on line 115.
In this simple scene there’s no issue, but in my full application my actors have axes at their center like this and they are large distances away from the world origin - 1e8+ meters as I’m visualizing the simulation of spacecraft orbiting earth and the moon. I have to be extra careful with my clipping ranges given single point precision in the depth buffer and this extra bounding box size is pulling the near clipping plane so far away my objects aren’t viewable.
My questions are:
- Is the bounding box of a
vtkAxesActorbeing affected by it’s world position a bug or intended behavior? - Is there a recommended workaround?
Appreciate any help you can provide! FYI @nchampag for additional awareness