Exploding dice variant: Can this be done?

I'm using an optional rule in a system where rolls are done on 2d6. The optional rule allows an 'exploding' die roll if BOTH dice turn up sixes, ie a 'Boxcar' result of a natural 12 on the roll. Is there a way to say 'roll an extra d6 and add to the total if the result of the 2d6 roll (before any modifiers are taken into account) is 12'?

Something like {0d1, 2d6 - 11}kh1 * 1d6 might produce what you want. I'm sadly not able to test it now.

Unfortunately, you want two separate things out of one dice roll. You want both the value and to explode it. Without the API, I don't think this can be done, unless you want to use Calle's option and then look at the grouped roll for the original 2d6.

Thanks Calle, I'll see what happens. I have no idea what that actually is of course, unless someone can explain it to me in idiot-proof language... What I want is for it to explode on a certain value. The only difference is wanting it to explode only on 2 dice both bearing that value, as opposed for EACH die with that value exploding. Instead of 'explode each die that's a 6', I want 'explode if BOTH dice say 6'.

Calle's roll will roll 0 1-sided dice (resulting in 0), and 2 6-sided dice (then subtract 11), and keep the higher result of the two. In other words, the first part will be 1 if you rolled boxcars, and 0 otherwise. Then he multiplies that result with 1d6. If you use /r {0d1,2d6-11}kh1*1d6 the "total" value that Roll20 displays will only be the exploding die (which will be 0 if you didn't explode), but you'll be able to see the 2d6 (they won't be summed, though). If you use an inline roll, you'll have to hover over the result in order to see the 2d6 values.

Thank you, but not quite what I'm after. There currently seems no way of exploding on a given total (or to compare to a compound result) as opposed to a result on a given die. On a related note, is there any way to 'store' a result from one roll and reference it as a variable for another subsequent function? Say within a macro?

Not without the API, no.

What exactly is this API?

Kit, the API is a mentor feature. This wiki page explains a bit more about it: <a href="https://wiki.roll20.net/API:Introduction" rel="nofollow">https://wiki.roll20.net/API:Introduction</a>

Thank you.