Rotate viewpoint while moving

[AndyGuatemala]

So I'm trying to make a train simulation in which the viewpoint moves forward and rotates by itself once it is close to an object.
I am able to make it turn while moving forward when I'm pressing down a key however, I can not figure out how to make it rotate smoothly without using a key. When I try using the setEuler without pressing a key, it turns however, it is not smooth at all. Any ideas on how to make it turn smoothly on its own?

[Jeff]

Create a spin action with the vizact.spinTo command and apply that to the viewpoint:
spinAction = vizact.spinTo(euler=[180,0,0], speed=30)
vizact.onkeydown(' ', viz.MainView.runAction, spinAction )