I think the solution to the floating blocks is airships – they’re higher than any building and so would allow you get on top of any any building, plus they move around so that adds an extra layer of complexity.

You also have physics options about penetration and the way such things are calculated to make it more accurate.

Looking at your code I would advise that you stop commenting every line of code, unlike what you might think commenting everything is a bad coding practice, comment only when the code itself isn’t clear about it’s purpose. Comments get quickly outdated leading to programming errors, adding to that they reduce the ability of one to see a bigger scope of the code on the screen, since at this point half the lines are comments.
Also for commenting methods/functions use XML comments which appear on intellisense popup making them far more useful than regular comments, since they describe the method/function and it’s parameters, all without even having to go to definition.

I would advise a quick read of a introductory book to c#/programming like head first c#, and something like c# in a nutshell as reference book, somethings mentioned in those books will not work in unity OFC, but most stuff does apply.
If you do not wish to spend time reading I would at least advise you grab a trial of visual studio 2013 (something above the express edition), and the trial of resharper since resharper will suggest alternative ways of doing things, will indicate unused variables, possible null references, and introduce you to lots of c# features that you might not know about, all around it will make your code far better, with very little time investment.

“Messing with angles to determine when to unwrap seems REALLY weird. Here’s what I consider a more correct way – Cast a ray to both the current grapple point, and that point’s parent (instead of just the parent as you were doing before). If you can see both, then it’d unwrap.

You may think this would cause issues if you traveled around an object completely, but then you’ll have created the new grapple points in the process of spinning around it anyways.?”

About the grapple rope going through things… that’s a much trickier solution. It’s delving into the realms of continuous collision detection, which is a crazy huge issue that’s been around for ages.

It’s much easier to find a solution which works “usually” than it is to find one that works in every case.

The easiest solution is just to check for collisions more. Instead of checking every rendering update, check every physics update which happens a lot more… of course, at even higher speeds (or with even thinner objects) it’s still miss.

The harder solution is to check against object’s corners for collisions instead of the whole thing, and then do some maths to find what corners are within the rope angle change between the previous frame and the current one, and then sorting them to ensure the new grapple points are created in the correct order. That *should* work in every situation, and will give improved accuracy to your current sim (where in some cases the line hits away from a corner then cuts through the object).

That is probably too much trouble to be worth it, though.