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Understanding Assembly Constraint Status

Ideally, when you complete a component’s placement, it should
be at a Fully Constrained status.
• Range of assembly constraint status:
– No Constraints
– Partially Constrained
♦ Packaged
– Fully Constrained
– Constraints Invalid
• The system can also Allow
Assumptions to facilitate component

Understanding Assembly Constraint Status 1
Figure 1 – No Constraints

Understanding Assembly Constraint Status 2
Figure 2 – Range of Assembly Constraint Status
Understanding Assembly Constraint Status
You can assemble a component into an assembly by using placement
constraints. Constraints determine how a part is located within an assembly.
As constraints are added, a component becomes further and further
constrained and progresses through a range of constraint statuses which
display in the dashboard. The constraint status range includes:
• No Constraints — No constraints have been added to the component being
assembled, as shown in Figure 1. The preview color of components having
no constraints is purple.
• Partially Constrained — At least one constraint has been applied to the
component being assembled, but not enough constraints have been added
to render the component fully constrained. That is, the orientation of the
component can still be changed, so its position is open to interpretation.
© 2012 PTC Module 19 | Page 11
For PTC Internal Use Only
The left-most image in Figure 2 shows the component Partially Constrained.
The preview color of partially constrained components is purple.
• Fully Constrained — Enough constraints have been applied to the
component being assembled that it cannot move. Ideally, when you
complete the component placement, the component should be fully
constrained. The right-most image in Figure 2 is Fully Constrained. The
preview color of fully constrained components changes to orange.
• Constraints Invalid — Two constraints conflict with how they are trying to
place the component in the assembly. If this condition arises, you must edit
or delete one or more constraints to eliminate the conflict.
Allowing Assumptions
The Allow Assumptions option can become available when placing a
component in an assembly. When this option is selected, the system makes
additional constraint assumptions to help fully constrain the component. If you
clear this check box, the system returns the status to Partially Constrained.
If you properly further constrain a component that is fully constrained with
Allow Assumptions enabled, the Allow Assumptions option disappears and
appears as Fully Constrained, as there is no longer a need for the system
to make assumptions. The middle image in Figure 2 is Fully Constrained as
long as the Allow Assumptions option is enabled. If the Allow Assumptions
check box is cleared, the component is no longer Fully Constrained, as it can
rotate. Either an additional constraint would need to be added or the Allow
Assumptions check box would need to be selected.
Leaving Components Packaged
If you complete the component placement when the status reads Partially
Constrained, the Message Log alerts you that the system leaves the
component packaged only. An open square symbol also displays in the
model tree next to the packaged component. You can drag components that
are packaged based on their partial constraints

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