One of my students is trying to convert from Tank Drive to Arcade Drive. They have the following code. The robot will drive forward and backward just fine, but when trying to turn it will turn the opposite direction.
LeftFront.spin(vex::directionType::rev, (controller.Axis3.value() - Controller.Axis4.value()/2, vex::velocityUnits::pct);
LeftBack.spin(vex::directionType::rev, (controller.Axis3.value() - Controller.Axis4.value()/2, vex::velocityUnits::pct);
RightFront.spin(vex::directionType::fwd, (controller.Axis4.value() + Controller.Axis3.value()/2, vex::velocityUnits::pct);
RightBack.spin(vex::directionType::fwd, (controller.Axis4.value() + Controller.Axis3.value()/2, vex::velocityUnits::pct);