if (getReferenceFrame() == desiredFrame) else if (getReferenceFrame() == getBaseFrame() && desiredFrame == getBodyFrame()) else if (getReferenceFrame() == getBodyFrame() && desiredFrame == getBaseFrame()) if (deltaTwist.getBodyFrame() == getReferenceFrame()) deltaTwist.checkBaseFrameMatch(getReferenceFrame()); flipCrossProducts = true; if (deltaTwist.getReferenceFrame() == getReferenceFrame()) throw new ReferenceFrameMismatchException("The given twists should be expressed in either: " + getReferenceFrame() + " or " + desiredFrame + " but were expressed in: " + deltaTwist.getReferenceFrame());