Alibre Design

Chapter 4 - Sketching• Dragging a B-spline by its endpoint to existing sketch geometry introduces a“fixed” coincident constraint between the B-spline and that figure.• Otherwise, dragging a B-spline to an existing reference point introduces a“floating” coincident constraint between the B-spline and that figure.• Dragging an existing reference point to a B-spline introduces a coincidentconstraint between the point and the B-spline. It is “fixed” or “floating”depending on whether the point was dragged to the B-spline's endpoint or aninternal location respectively.‣ To move a spline curve rigidly:1. Choose the Select tool from the Sketching toolbar.2. Click and hold the mouse button on the curve, and drag the spline curve.3. Release the mouse button to place the curve.Trimming and extending spline curvesThe B-spline curve can be trimmed using other figures (lines, arcs, circles, ellipses andB-splines).Open figures like lines and arcs can be extended to the intersection point with a B-spline curve. However, the B-spline curve itself cannot be extended.Spline curve shape modificationAn assortment of methods is available to modify or tweak the B-spline curve's shapewhile still honoring all the constraints placed on the curve. These tools take advantageof the excellent local shape modification properties of B-splines.‣ To modify a spline curve's shape:From the Sketch menu, select Figures > Spline > Edit > Desired ActionPossible Actions:Move Control Points - Modify shape by moving a control point62