So for the past few days I've been attempting to work out a way to get a character to walk down a spiral staircase. As you may know Antics allows you to simply point and click your way to stairway heaven, so long as you use the Antics stairs. If you do wish to import a set of stairs from Sketchup you'll have to take some further steps to get the action to work. The workflow goes like this: Import your staircase. Count the steps. Create an antics staircase with equal steps. You'll probably have to scale the imported asset to match. If you're lucky you'll be able to align the stairs so that the character appears to walk on the imported one. Most probably, the imported stairs will be taller or longer. You can overcome this by moving the staircase whilst the character is ascending/descending. The probem though, is that you cannot simply move the staircase alone, if you do so then the character won't know where the stair starts/stops. So you move the room that contains the whole lot.
Ok, so that's how the straight line setup works, but what if I want to use a spiral staircase? Well, as I found out, this required much more head stratching! I tried lots of things, camera key- framing, poses, linking to axial billboards.... The problem was how to build the rotation into the setup, given that the rotation needs to be relative to a character who is moving.I sorted this problem out by moving the staircase/room in "z" and "x" axis. This gave me the illusion of the character walking the wrong way up an escalator. That is, the character is doing the stepping action but not actually moving in any direction. The idea was then to get the whole room to move around a centre pivot and float down the centre pole of my spiral staircase. O.K. if you followed that you've done very well. The problem was, it was a nightmare to setup!! I think it worked once but there were plenty of errors and it was really unreliable.
So I abandoned the idea of using the stepping action and set about just using a walking action. I built a long corridor of a room, one that would allow my character to take the same amount of a steps as I had in the spiral staircase. I then moved the room, so she just walked on the spot (like a treadmill). Then I had this setup move through a series of poses to get the rotation and z position correct. A lot of work, but it turned out ok. here