All the internal calculations of JSCAD (and other included libraries) are based on the 'right-hand' rule. (For more information see discussions here and here.)

This results in the following orientation of the three-dimensional coordinate system, i.e. orientation of X, Y, and Z axis.

• Positive X points to the right
• Positive Y points to the back
• Positive Z points to the top

This also means that positive rotations are

• From positive X to positive Y about the Z axis
• From positive Y to positive Z about the X axis
• From positive Z to positive X about the Y axis

It may take some time to understand well, and can be visualized by rotating shapes by both positive and negative angles.