Before you can use the Parametric Design solver to generate variations from an existing part, each element in the zone must have one or more constraints assigned to it. Enough constraints must be assigned to tell the solver exactly what to do with each element in the part. If elements in the zone are not fully constrained or are incorrectly constrained, the solver will not be able to generate the variation.

The best way to assign a full set of constraints is to first constrain all the elements in the part in their current configuration. After the part is fully constrained in its current configuration, you can modify constraints as needed to generate a variation.

Both manual and automatic options are available for assigning constraints. Typically, the manual options are used to assign a few important constraints like reference elements, and then AUTO is run to generate the remaining constraints needed to fully constrain the part.