In addition to the shared parameters above, it defines the following parameters.

The tolerance element defines the augmentation tolerance. That is, when the relative change in the constraint forces and moments (the Lagrange multipliers) are less than this value. The gaptol element defines the tolerance for spatial separation of the joint origin on the two bodies (in units of length). The angtol element defines the tolerance for angular separation of the joint axis on the two bodies (in units of radians). Setting any of these three elements to zero disables the enforcement of that tolerance. The force_penalty parameter (with units of force per length) represents the stiffness that prevents the joint origin on the two bodies from separating. The moment_penalty parameter (with units of moment per radians) represents the torsional stiffness that enforces parallelism of the joint axis on the two bodies. The body_a and body_b elements are the material numbers of the two rigid bodies. The joint_origin element defines the position of the joint (the origin of the basis $\left\{ \mathbf{e}_{1},\mathbf{e}_{2},\mathbf{e}_{3}\right\} )$ in world coordinates at the start of the analysis. Note that this point does not have to be inside or on the surface of either of the two bodies. The joint_axis element defines the orientation $\mathbf{e}_{1}$ of the joint rotation and translation axis in world coordinates at the start of the analysis.

Optionally, the rotation of body $b$ relative to body $a$ may be prescribed using the additional tags

<prescribed_rotation>1</prescribed_rotation>
<rotation lc="1">1.570796327</rotation>

Optionally, the translation of body $b$ relative to body $a$ may be prescribed using the additional tags

<prescribed_translation>1</prescribed_translation>
<translation lc="2">10.0</translation>

<moment lc="1">5.e-3</moment>

Optionally, a force may be prescribed along the joint axis using the additional tag

<force lc="1">2.0</force>

Example:

<constraint type="rigid cylindrical joint" name="Joint03">
  <tolerance>0</tolerance>
  <gaptol>1e-4</gaptol>
  <angtol>1e-4</angtol>
  <force_penalty>1e0</force_penalty>
  <moment_penalty>1e0</moment_penalty>
  <auto_penalty>1</auto_penalty>
  <body_a>1</body_a>
  <body_b>2</body_b>
  <joint_origin>0,0,0</joint_origin>
  <joint_axis>0,0,1</joint_axis>
</constraint>