Improve CAD viewer camera

[je-cook]

Description of issue / requirement to address

Our freecad cad viewer has a slight hack in it that rotates the CAD instead of the camera of the viewer

Proposed solution

The camera can be accessed here:

bluemira/bluemira/codes/_freecadapi.py

Line 2407 in 4eb7987

viewer.setSceneGraph(root)

with some of the below dump of exploratory code being useful, its half translated from c++ ie the pointers dont work:

    camera = viewer.getSoEventManager().getCamera()
    cam_pos = camera.position.getValue().getValue()

    direction = (0, 0, -1)
    orient = s
    direction *= orient

    focal_point = cam_pos + camera.focalDistance.getValue() * direction

    # rotation_dist = camera.focalDistance.getValue() * coin.SbVec3f(0, 0, 1)
    # new_rot_cen = orient * = rotation_dist
    front_orient = np.sqrt(2) / 2

    orientation = (front_orient, 0, 0, front_orient)
    # // Distance from rotation center to camera position in camera coordinate system
    rotationCenterDistanceCam: SbVec3f = camera.focalDistance.getValue() * SbVec3f(
        0, 0, 1
    )

    # // Set to the given orientation
    camera.orientation = orientation

    # // Distance from rotation center to new camera position in global coordinate system
    newRotationCenterDistance: SbVec3f = camera.orientation.getValue().multVec(
        rotationCenterDistanceCam, newRotationCenterDistance
    )
    # // Reposition camera so the rotation center stays in the same place
    # // Optionally add translation to move to center

    camera.position = focal_point + newRotationCenterDistance

    # vprt = coin.SbViewportRegion()
    # action = coin.SoGetBoundingBoxAction(vprt)
    # root.getBoundingBox(action)
    # action.getBoundingBox().getSize().getValue()

With the above you need to remvoe the rotate=True from the viewer and the rotate argument completely as mentioned in #3235

Alternative solutions

leave as is, it does work.

Additional context

This may lead to us being able to specify the viewing angle say for an autogenerated image in future.