Constraints

The most frequent constraints are:

• Offset between the Base point and a point in the Tooling assembly (main tooling constraint),
• Offset between the Base point and a plane in the Tooling assembly (secondary tooling constraint).

For the general case, only local, point and planar mode are available.

Tooling constraints are pre defined by the choice of working mode.

In planar mode :

• The working plane cannot be replaced by another plane in the main Tooling Constraint.
• The constraining point may be different for different preview instances for each secondary Tooling Constraint.
• Some previewed instances may have a secondary Tooling Constraint and some not.

In point mode :

• The Tooling Assembly current plane is defined as follows:
  • If some selected points are on a plane, the first Plane associated to a point in this manner (first in the sense of selection order) becomes the current plane.
  • It is not overloaded if points on other planes are selected afterwards.
  • It is possible at any moment to overload the current plane by 3D graphic selection of a plane. (But note that such a selection will also modify the axial direction of the previews which will all become normal to the selected plane )
• The point defining the point mode for a given preview cannot be replaced by another point in the main Tooling Constraint.
• A different point may be used as constraining element for each previewed instance.
• The constraining plane is identical for each previewed instance.
• Either all or no previewed instances have secondary constraints.
  In particular, even if some points are associated to planes and some not, the secondary constraints are created
  (with the current plane in all cases).

In local mode:

• If the local mode is active because an existing instance of a Tooling Component was selected, then the Tooling constraints for all the previews are deduced from the Tooling constraints of the selected instance : their number, their nature , the constraining element on the Tooling Assembly side is the same.
  Before the preview is moved, the offset values are the same.

The point constraining element is dedicated to each preview, the plane constraining element is shared by all previews, the Tooling Assembly element defined for the main tooling constraint cannot be overloaded after the working mode has been defined (this is more a restriction in planar mode than in point mode, because the constraining plane is shared by all previewed instances).

Nature of Constrained Elements in the Tooling Component

Automatic constraints :

• Only the Base point of the Tooling Component is constrained.
• It may be involved in zero, one or two automatic constraints.

Manual constraints set by the user , with assembly command. See above.

The Tooling Component is said to be constrained.

Nature of Constraining Elements in the Tooling Assembly

The constraining element can be :

• a plane (existing),
• a point (existing),
• both,
• nothing.

The Tooling Assembly Component is viewed as constraining.

In all cases, the element allowed to move is the Base point of the component, and the constraining element in the Tooling Assembly is not allowed to move (oriented constraint concept).

Consistency between constraining elements in the Tooling Assembly side

In planar mode, it is not possible to automatically create constraints with a point which is not at zero distance from the plane.
In point mode there are no specific rules.

Replacing constraining elements

Within some limits, it is possible to replace a constraining element by another of same type.
Replacements are accepted only in the general case, and only when there is a single constraint:

• point in a “base point – point” offset constraint,
• plane in a “base point - plane” offset constraint.

It is very highly recommended to replace a plane by a parallel plane because otherwise the interpretation of the offset becomes difficult.

In planar mode, the constraining plane is not shared between all the previewed instances.

Rule on Multiple Constraints

To avoid inconsistencies, when a preview is subjected to several constraints, e.g. point offset and plane offset, it is not possible to replace any of them.

Effect of replacement

Replacement of a constraining element has two distinct effects:

• it modifies the candidate for constraining element in the Tooling Assembly side,
• it moves the active preview to make it consistent with the current constraint (offset with plane or offset with point).
• Mold Tooling Design automatically solves the constraints and update the position of the active instance during replacement of a constraining element.
• The coordinates of the moved anchor point (X,Y,Z) and (U,V,W) are automatically updated.

The positioning elements and the local axis system are not modified by the replacement of the constraining elements.