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I'm trying to make a spiral staircase that goes up through the inside of a cylindrical building. Doing the stair treads is easy enough, but I don't know how to get the collision ramp to conform to the inside of the building. I tried using a curve to get the spiral and then using that as a deformer for the mesh, but that didn't work well at all. Any tips?

Thanks

There are numerous ways to do it, extruding along curves, shrink wrap, drawing polygons from front-top edge of each step to the next etc.
I just tried the last method and it only took about 3 minutes to draw a polygon ramp from step to step while using point snapping, and once I got a 360 degree section I just copied and translated up and merged with the first.

Example:
http://www.mediafire.com/download/blfl4 ... lision.zip

Interesting, thanks. That's much cleaner than what I originally did, where I used a curve as the deformer after freezing the transforms of my cube (otherwise it twists). So in your example, you made the steps first, right? And then drew in the collision after? If so, how did you curve the steps in the first place? I figured I would manually place individual steps and then let xsi's smart duplication take over to add the rest.

Oceans14 wrote:So in your example, you made the steps first, right? And then drew in the collision after?

Correct.

Oceans14 wrote: how did you curve the steps in the first place?

I just started with a disc and the number of subdivisions I wanted.
Then selected all but one polygon and ctrl+d to extrude while holding ctrl to constrain distance as I translated upward, then selected all but two polygons and repeated this process around until i reached the end, and this gave me all the treads and risers I needed.
I then selected all the tread and riser polygons and inverted the selection and deleted the unwanted polygons.
Then I scaled the remaining geometry to get the exact proportions I wanted, and finally used a cylinder with the same number of subdivisions to boolean difference the gap seen in the center where a support post would go.
It sounds like a lot of work but only took a few minutes, and of course the purpose of this example was to demonstrate spiral stair collision and was just a 2d staircase, I could easily make it 3d as well.

Keep in mind your AI paths cannot overlap, so make sure your staircase doesn't make a full rotation. If the paths overlap the AI will either ignore it or get really confused.

@AceMastermind - genius, that's so much less work than using deformers honestly. And since I'm putting the stairs inside a windmill, I can match subdivisions so that the stairs conform to the wall.

@Teancum - right, so the ai would have an awful time in there. I think I'll probably just barrier it off and make it a human-only building.

I very much appreciate the help, there isn't actually very much info on this in the xsi docs or online.

Teancum wrote:Keep in mind your AI paths cannot overlap, so make sure your staircase doesn't make a full rotation. If the paths overlap the AI will either ignore it or get really confused.

So long as the paths are the same all the way up it should be fine, but you can't have two levels above each other unless the paths are comaptilbe, you'll have issues, this is because: There is no height limits to paths, so they go all the way up, and things get weird if they overlap, (CURRENTLY).

Imagine it in your head, looking down, a path on the ground floor, goes right up to the skybox, so as long as the AI can follow all the paths on both levels, you're okay.