Rotation: How Do I Calculate The Right Rotation?

I wonder how I calculate the right rotation for a road buildings plug?

Trail and error is taking to long time. Even if one only use 90 degree turn on each axle, change settings, pack the patch, start the game, start map, test, quit, even it all that only take 3 min per time I will have to do it 64 times, and that is more then 3 hours worth of testing.

I do hope there is some one that have easy or complex equations, for me to use. Then I wold be happy.

When one look at quarterninions on wiki there is so much information that I don't realy now what to use.

Regards
OokamiChan

 

Plug of road <-> plug road building.
The road plug have one rotation and that will not change.
But the rotation for the plug on road buildings change depending on x, y, z coordinates that the plug is sitting on.
So plug A have x=-5 y=40 and z=0, Plug B have x=5 y=40 z=0. Even if both plugs is on the top end of the road building won't mean that plug A and plug B will have the same rotation. It depends also on witch end of the road that is connecting to the road building plug, top or bottom.

A week ago I did some testing and after around 1 hour and 1/3 of all possible settings, I hoped 90 degree per rotation, I did find 5 possible settings that worked for the same plug and there is possible 1 to 3 more settings that I didn't find.

I just wish to have an equation that will let me calculate the different rotations with out an trail and error approach, or as few trail and error as possible.

Regards
OokamiChan

 

Sorry for the long replay. I'm trying to make the pictures, so far I have one of where the rotation is wrong. I hope to get one or two more soon.

Regards
OokamiChan