OK, I serched and could not find so here goes.
I have a cable attached to two points and as the points move apart I want the cable to break free of one of the ends or even better some place along the length. A quick tip like “here is a link to your solution try a better serch next time meat head” would be most welcomed...lol.
I am using Reactor rope...and I have each end attached to a rigid body.
Thanks in advance.
FYI YouTube links do me no good...BLOCKED at work.

3ds Max 9 thru 2013
Windows 7 Enterprise 64-bit OS SP1
Dual Intel® Xeon® 6 core X5650 @ 2.67GHz CPU 36GB RAM
NVIDIA Quadro 4000
450GB HDD (x3) and 2TB HDD

3ds Max 2012 Certified Professional Models to Motion

I don’t know of a way of directly breaking a reactor rope. But reactor does have breakable constraints that can be applied to Rigid Bodies, so you could maybe attach the rope end to an RB with a breakable constraint to another RB, sortof like this. The other trick I mention there is simming up to breaking point, stopping, removing the constraint/link, then continuing thew sim, though that may not a tension twang effect. Getting it in the middle (or anywhere eles along the rope) is even harder since you cant attach a rope to rope directly.
An alternative is a cloth dynamic solution, see these cloth tearing tuts by Joe Gunn, for newer versions of cloth and for older versions.
I do hope you are able to watch Joe’s tutorials there.

Thanks...I will to look at all of this! (**edit** I was able to view them)
All I really need is for the one end of the rope to “let go” of the rigid body for this one but couldn’t figure out how to do that in the middle of the sim. Can you “key” the “unyeilding” button? (**edit** was not able to)

3ds Max 9 thru 2013
Windows 7 Enterprise 64-bit OS SP1
Dual Intel® Xeon® 6 core X5650 @ 2.67GHz CPU 36GB RAM
NVIDIA Quadro 4000
450GB HDD (x3) and 2TB HDD

3ds Max 2012 Certified Professional Models to Motion

Can you “key” the “unyeilding” button? (**edit** was not able to)

No, it cannot be keyed, but the workaround is to run the sim up to the breaking point, eg, frame 0 to 49 with it on, then turn it off, run a sim from frame 50 to 100, the rope will fall off at frame 50.

That was the part I didn’t think of because I didn’t think about changing the “start” frame of reactor. I had it in my head that once you re-run reactor everything resets and sims all over again. I now can run the first 100 frames or so once and then just change it to run the rest as I modify the sceen to get what the engineer wants. Thank you again so much.

3ds Max 9 thru 2013
Windows 7 Enterprise 64-bit OS SP1
Dual Intel® Xeon® 6 core X5650 @ 2.67GHz CPU 36GB RAM
NVIDIA Quadro 4000
450GB HDD (x3) and 2TB HDD

3ds Max 2012 Certified Professional Models to Motion

I did what you said but now the end of the rope that I change the RB check box on just stays put...IE doesn’t fall like it should, hangs in space!!!

3ds Max 9 thru 2013
Windows 7 Enterprise 64-bit OS SP1
Dual Intel® Xeon® 6 core X5650 @ 2.67GHz CPU 36GB RAM
NVIDIA Quadro 4000
450GB HDD (x3) and 2TB HDD

3ds Max 2012 Certified Professional Models to Motion

Does the RB have Mass? You could maybe do without the RB and remove the link on the rope instead.

I had to delete the link to the RB...that worked.
Sad thing is I have had to redo the link like 5 times already, then del it.
(PITA)

3ds Max 9 thru 2013
Windows 7 Enterprise 64-bit OS SP1
Dual Intel® Xeon® 6 core X5650 @ 2.67GHz CPU 36GB RAM
NVIDIA Quadro 4000
450GB HDD (x3) and 2TB HDD

3ds Max 2012 Certified Professional Models to Motion