Constraint Mates

Constraint mates offer higher pair constraints in the form of distance, coincidence and tangency between two analytical geometries. The geometries could be point, line, sphere, cylinder, cone or a plane. The geometry is defined analytically using bodies and points.

Certain type of constraints may not be applicable based on the geometry involved.

  1. If the Advanced Joint panel is not currently displayed, select the desired advanced joint by clicking on it in the Model Browser or in the modeling window.
    The Advanced Joint panel is automatically displayed.
  2. From the Connectivity tab, select the general mating type of the constraints. If Distance is chosen, enter a value in the Distance field.
    Each constraint type further provides various geometric methods to constrain one body with respect to the other body. For example, a general mating constraint type of Distance can be defined between two bodies (Body 1 & Body 2) in order to ensure that a constant distance is maintained between a point on Body 1 with regard to a line on Body 2. In this case, select Point from the Geometry 1 drop-down menu and Line from the Geometry 2 drop-down menu.
    Note: The corresponding MotionSolve argument under the Contstraint_Mate statement is DIS_POI_LIN.
  3. Specify the geometric methods of constraint for Geometry1 and Geometry 2 using the drop-down menus.
  4. Click the Geometry 1 tab and define a body, point, orientation and radius (if applicable) for the type of geometry selected in the Connectivity tab.
  5. Similarly, define the geometry in the Geometry 2 tab.
    Note: The entity selections which are available for the Geometry1 and Geometry2 tabs are dependent on the constraint and geometry types specified in the Connectivity tab.

Point

  1. Click the Body collector and select the body constrained by the constraint mate.
  2. Click the Point collector and select the point on the body to be constrained.

Sphere

  1. Click the Body collector and select the body constrained by the constraint mate.
  2. Click the Point collector and select the sphere center.
  3. Enter a value for the radius of the sphere.

Line

  1. Click the Body collector and select the body constrained by the constraint mate.
  2. Click the first Point collector and select the origin of the line.
  3. Use the second Point collector to select the point that defines the line from the origin, or, using the drop-down menu to the left of the collector, select Vector and define a vector.
    Note: The marker on Body 1 (I marker) is defined at the line origin and the Z axis of the marker is oriented along the direction defined by the Point|Vector that defines the line. The same applies to the marker on Body 2 (J marker) in the case of the Geometry2 tab.

Cylinder

  1. Click the Body collector and select the body constrained by the constraint mate.
  2. Click the first Point collector and select the origin of the cylinder axis.
  3. Use the second Point collector to select the point that defines the axis of the cylinder, or, using the drop-down menu to the left of the collector, select Vector and define a vector.
  4. Enter a value for the radius of the cylinder.
    Note: The marker on Body 1 (I marker) is defined at the cylinder axis and the Z axis of the marker is oriented along the direction defined by the Point|Vector that defines the axis. The same applies to the marker on Body 2 (J marker) in the case of the Geometry2 tab.

Plane

  1. Click the Body collector and select the body constrained by the constraint mate.
  2. Click the first Point collector and select the origin of the plane axis.
  3. Use the second Point collector to select the point that defines the axis of the plane, or, using the drop-down menu to the left of the collector, select Vector and define a vector.
    Note: The marker on Body 1 (I marker) is defined at the origin of the plane and the Z axis of the marker is oriented along the direction defined by the Point|Vector that defines the plane normal. The same applies to the marker on Body 2 (J marker) in the case of the Geometry2 tab.

Cone

Note: This option is only available for the Geometry2 tab.
  1. Click the Body 2 collector and select the second body constrained by the constraint mate.
  2. Click the Point collector and select the base point of the cone.
  3. Use the second Point collector to select the point that defines the axis of the plane, or, using the drop-down menu to the left of the collector, select Vector and define a vector.
  4. Enter a value for the radius of the cone base.
  5. Enter a value for the height of the cone.
    Note: The marker on Body 2 (J marker) is defined at the base of the cone and the Z axis of the marker is oriented along the direction defined by the point/vector that defines the cone height.

MotionSolve Keywords

The table below summarizes the various combinations of geometry choices along with the keyword TYPE that is written to the Contraint_Mate statement for MotionSolve:

Constraint Type Geometry 1 Geometry 2 MotionSolve keyword (TYPE)
Distance Point Point DIS_POI_POI
Sphere DIS_POI_SPH
Line DIS_POI_LIN
Cylinder DIS_POI_CYL
Sphere Sphere DIS_SPH_SPH
Line DIS_SPH_LIN
Cylinder DIS_SPH_CYL
Cone DIS_SPH_CON
Plane DIS_SPH_PLA
Line Line DIS_LIN_LIN
Cylinder DIS_LIN_CYL
Plane DIS_LIN_PLA
Cylinder Cylinder DIS_CYL_CYL
Plane Cone DIS_PLA_CON
Cylinder DIS_PLA_CYL
Coincident Point Cylinder COI_POI_CYL
Sphere COI_POI_SPH
Point COI_POI_POI
Line COI_POI_LIN
Cone COI_POI_CON
Line Cylinder COI_LIN_CYL
Plane COI_LIN_PLA
Line COI_LIN_LIN
Tangent Sphere Line TAN_SPH_LIN
Cylinder TAN_SPH_CYL
Plane TAN_SPH_PLA
Cone TAN_SPH_CON
Sphere TAN_SPH_SPH
Line Cylinder TAN_LIN_CYL
Cylinder Cylinder TAN_CYL_CYL
Plane Cylinder TAN_PLA_CYL
Cone TAN_PLA_CON