• LineOnCylinder3[cnum, axis1, axis2, rad] constrains axis1 to lie parallel to axis2, and rad units away from axis2.
• LineOnCylinder3 constrains three degrees of freedom.
• LineOnCylinder3 becomes singular if rad is set to zero. Cylindrical4 should be used instead.
• The first two equations constrain the two axes to be parallel, the third equation constrains the two axes to lie rad units apart.
• See also: LineToLine1, ParaRevolute4, SetConstraints, SysCon.