In imagination, there's no limitation.
Mark Victor Hansen
Constraint limits have got to be one of the coolest things I've run across in Inventor so far.
In the past, when we've wanted to limit the range of motion for an assembly, we had Positional Representations, and Contact Sets to fill that roll.
Both tools work great, I use them, and I'll continue to use them in the future. For example, using the cylinder assembly below as an example.
Postional Representations are great for creating an 'extended or retracted' scenario, they couldn't let the assembly move between those extremes. Positional Representations can create snapshots in the motion.
Contact Sets, on the other hand, could allow an assembly to move between two positions, but the parts have to physically contact each other. So in our example, the piston inside the cylinder would have to hit the endcaps to stop. This might not be good for the life of the piston.
But now we have Constraint Limits! These set the limits on a constraint offset so the piston moves through it's motion, but I can define the offset in such away that piston doesn't hit the endcaps.
Here's a video showing the new tools!
So far, this is sizing up to be one of my favorite Inventor 2011 features!