The closest thing on the market I know of that is close to "limit constraints" is in Solid Edge. They have "sensors" which are just values you put on onto a variable (dimension). Once the dimension goes outside the values set up in the sensor, a warning goes off. IT DOES NOT PREVENT THE USER FROM EXCEEDING THE LIMIT, though. If Alibre came out with limits constraints, it would be first on the market to accomplish such a thing.
<As Scott steps up on his soapbox>
There are actually 2 things that the MCAD market in general has to develop in the near future in terms of limits: dimensional tolerances and assembly constraints.
In terms of dimensional tolerances, the application needs an easy way to apply standard and specific tolerances to every dimension on the model so MMC and LMC and mean conditions can be checked for form fit and function (tolerance stackups). I would hate to see an upper and lower limit show up in my equation editor/variable table for each dimension I place. Nothing like having 9 variables listed to define a cube.
In terms of assembly constraints, the application needs an easy way to allow for the tolerance stackup from the above. Yes, I want to align these two holes, yes I know they are .005 inches off, but a bolt will still fit through so do it. Tell me, but do it. If a bolt wouldn't fit through, then don't apply the constraint. Movement also applies to this area. In the example in earlier posts, I have a part that can clock X number of degrees, I want to give it that freedom to rotate, not lock it into just one position.
Maybe v10.
<As he steps down from his soapbox with head held low.>