Preview from SpringArm3D spring length

[vaner-org]

Hello. I love your plugin, its been very useful.

I was thinking that it would be helpful to have the camera automatically traverse to the edge of a parent SpringArm3D, if one exists.

In my game, my player's camera is interpolated to new positions when there is need for a fixed camera, and these camera rigs mimic the tree of my player camera. Unfortunately, because the camera ultimately is a child of a SpringArm3D, checking these requires me to write a script to move its local z to be -spring_length in the editor and revert on run.

Of course I don't expect it to actually test collision with the SpringArm unless it is computationally non-trivial.
I hope it is worthwhile to accommodate this use case.