Contact Constraints

ascenari.gif (1364 bytes) The Contact Constraint creates a constraint between a segment and a point, a line, or a plane.

After selecting the command and a manikin segment, the system prompts you to select a point, a line, or a plane.

Point contact constraint

The point selected is linked with the end effector of the segment.

Line contact constraints

The two types are line contact and line with direction contact. Line contact is the default at creation.

Line contact

The segment end effector is in contact with the nearest portion of the target line. For example, if the end effector is a finger, and the target is a part of a box, the tip of the finger would try to touch the specified line of the box.

Line with direction contact

To convert the default line contact constraint to a line with direction constraint, use the Constraint Properties dialog box.

Plane contact constraints

The two types are 2 directions plane contact and 3 directions plane contact. 2 directions plane contact is the default at creation.

2 directions plane contact

The end effector is placed on a point in the center of the surface i.e., the center of a cube side, parallel to this surface. The orientation of the hand is not defined.


3 directions plane contact

To convert to the 3 directions plane contact constraint, use the Constraint Properties dialog box.

The end effector orients itself with the three directions of the surface, as shown below. The arrows indicate the orientation of the end effector on the surface. The end effector can be modified in the Constraint Properties dialog box.

  1. In the Manikin Constraints toolbar, select  Contact Constraint.

  2. Select a manikin segment.

  3. Select a point, line, or a plane on the box.

By default:

  • The name of the constraint is ConstraintX where X is an incremental number.
  • The constraint type is "2 directions Plane"  for a plane contact constraint and "Line" for a line contact constraint.
  • The constraint priority is 1
  • The constraint is activated

Editing default properties

These default properties can be edited in the Constraint Properties dialog box. To access this dialog box do one of the following:

  • In the 3D view, double-click on the constraint.
  • Double-click on the constraint in the specification tree.
  • In the 3D view, right-click on the constraint and select Definition... in the contextual menu.


Name: Accept the assigned default name or rename as desired.
Manikin: You may use the manikin originally selected or, in the 3D view, select a new manikin.
Segment: Shows the selected segment. The combo box allows you to select the right or left side of the body for the current constraint. The control is disabled when the current segment is independent of the body side, i.e., the head.  If the arm was selected instead of the hand, if the move to posture changes, the update will not modify the constraint.
Object: The object in the 3D view that shares the constraint with the segment.
Type: Can be "2 directions" or "3 directions" when the selected object is a plane and "Unavailable" when the selected type is a point or a line.
Priority: The priority is in terms of relative weight between the constraints. In a multi-constraint environment, a constraint with priority 1 will be given the most weight, and a constraint with priority 4 will have the least weight. These relative constraint weights will be considered by the software if the following conditions are true:
  • There must exist at least two active constraints on the manikin;
  •  These constraints must be on different kinematic chains;
  • The system must find no solution to resolve all constraints together.
Passing Criteria: Set a criteria that defines the maximum allowed distance and/or angle between the segment's end effector and the target object.
Result: Shows the actual distance and angle between the segment's end effector and the target object. The text "Success" or "Failed" is displayed depending whether the distance (length of constraint) is superior or inferior to the criteria.