Curve Creation
These parametric curves can be created:
- Through an intersection
or projection
of 3D geometry in the sketch.
After
isolating the resulting geometry, you can use constraints to change
the position of the curve. The system is unable to directly modify the
shape because the curve, which has no internal freedoms that the system
can control, only has three degrees of freedom.
- By using Spline .
The curve is defined from other geometries. The parametric curve is
said dependent. It is constructed so it passes through a series of control
points.
Constraints and dimensions can be added between a dependent
parametric curve and other geometries in the sketch.
Solving problems will occur:
- If the position of the defining geometry depends upon the position
of the parametric curve, either directly or indirectly.
- When the other geometry of the constraint or dimension is an other
parametric curve or dependent parametric curve.
Recommendations
Always use Constraint without dialog box
to specify where the constraint must be created on the curve. When using
this command, selection points are not taken into account.
On fully under-constrained sketches, the system can
have difficulties in choosing between changing the shape and/or moving its
defining geometry especially when it supposes to make large changes. Moving
the geometry helps the system find a consistent solution in that case.