As stated in the title, I need to know how to do this, specifically for my new map. I need to put a crate on top of a double box in order to make a stepping stone to get to a higher double box. I did find a guide to merging immovable objects, but none on interlocking. Thanks in Advance!
Interlocking works for everything in the same way. It's just if you don't brace half the things, they get sent out. An excellent draw bridge was made on avalanche by interlocking multiple crates, using teleporters as braces and when you stepped on a custom power-up it disappeared, and the custom power-up was the only brace in a certain direction, so the interlocked movable objects shot out in that direction.
You don't have to merge the crate to be able to get to the next double box. It should be short enough to just jump.
mabey this will work. if its the short side up, use 2 dumpsters and put a single box on top. then spawn the double box. then you have a platform halway between a double box and 2 double boxes. if its long side up spawn a single and and then do what it says above but on the single.
Interlocking won't prevent the crate from moving. You'd have to brace it to make sure it wouldn't move while interlocked, so just skip the interlocking and brace it with teleporters. While interlocking moveable with immovable objects is possible, it requires permanent braces to ensure the moveable object doesn't flip out, so there's really no reason to.