Sketcher in CATIA

Solving Inconsistent Elements
See Full-Size ImageOverview: Sketcher, the cornerstone of CATIA, is one of the most useful tools in CATIA. It allows you to quicklycreate parametric profiles to begin a part. Not only does it create the base profile for the model but also nearly all subsequent solidoperations are sketch based. In fact, CATIA is one of the most heavy sketch-based modelers around. Although Sketcher is a powerful tool,numerous times elements become inconsistent. This is usually due to someone creating elements out of scale or having conflicting dimensionsand geometry. Below are some strategies to solve some common problems.Auto Constraint Auto Constraint is one of the most useful tools in the Sketcher workbench. It allows you to quickly add both dimensional andgeometric constraints to sketch elements. Before you create the constraints make sure you think about what you want to constrain and whatreference elements you need. Blindly selecting all the elements and any reference element will create a mesh of meaningless dimensions.Instead, think about the design intent. Choose the elements that you need to control dimensionally and by which edge in the model, and thenapply the automatic constraints.Dragging Elements Since CATIA gears the Sketcher around the rapid creation of profiles, there are times that it is difficult to constrain a sketch. Youmight find that increasing the value of a dimensional constraint causes the sketch to become over constrained, or some of your sketch curvesreact to the change in an undesirable manner. A number of things can cause over constraints, but it is usually the designer creating a sketchout of scale. Dragging the sketch elements allows you to dynamically move the elements to position them so they are constrained correctly. Toallow direct dragging of elements select Tools Options, Mechanical Design, Sketcher and activate Allow directmanipulation in the Options dialog.Animate When you roughly create elements and then apply constraints one at a time, sometimes the sketch becomes inconsistent. This is due tocreating the elements out of scale and CATIA cannot resize the elements to the correct size without causing conflicts. Animate Constraintallows you to narrow down where the values in the sketch become inconsistent. When you narrow down the selection, modify the dimensioncausing the problem to the value at just below where the sketch becomes inconsistent and then modify the other dimensions in smallincrements. By doing it this way, you should be able to solve any inconsistent dimensions that appear.Scale If you cannot drag the elements into the correct position or use Animate to pinpoint the problem areas, use Scale to increase ordecrease the size of the elements. Deactivate Duplicate mode in the dialog to only move the elements...................