I have done a fair bit of searching and have come up with nothing. Sorry in advance if this has been covered. Symmetry when using reverse-facing couplers does not seem to work as expected in the SPH. At least this is the case for me. Example: Base bi-coupler. Left symmetry bi-coupler. Right symmetry bi-coupler. Base is oriented so the single coupler is facing the front of the ship. Left and Right are oriented with the single coupler facing the back of the ship. If I try to do symmetry off the left side of Base, Left will look as expected with the right side of Left connected to the left side of Base. The left side of Right does not connect to the right side of Base as I would expect but rather connects to both sides of Base. Here is a visual aid: This is what I want: __o*o *o*_*o* This is what I get: __o*o *o*o* When I use the bi-couplers facing in the same direction, symmetry works as expected. When I use the VAB, symmetry works as expected with opposite facing couplers. My game was modded when I noticed this. Uninstalling KSP, deleting all remaining files from the install directory and re-installing did not change the outcome.