Part Modeling
Features build history
A part is a sequence of features evaluated in order. Understanding the end-of-part marker, feature reordering, and suppression is essential. Sketched features consume a profile; placed features, such as fillet, chamfer, hole, shell, draft, and thread, modify existing geometry without a sketch. Work features, including planes, axes, and points, provide references for both.
Concepts to master
Know extrude options, including join, cut, intersect, and new solid, and the difference between distance, through-all, and to-face termination. Understand revolve requirements, sweep and loft with their profiles and paths, and how patterns and mirrors propagate features. Learn the hole command and its standards, the sheet metal environment's distinct rules, and multi-body parts. Understand parameters and how equations drive dimensions.
Traps in questions
A frequent trap is assuming a feature can always be reordered; parent-child dependencies limit this. Another is confusing a pattern of features with a pattern of bodies. Questions may ask what happens when a sketch is consumed by a feature, or whether a suppressed feature still drives dependents. Watch for items on termination types, where to-face and through-all behave differently when the model changes. Also expect questions distinguishing a derived part from a copy.
Worked example
If a fillet fails after an upstream change, the cause is usually a lost edge reference. Rule of thumb: place cosmetic features such as fillets and chamfers late in the tree, and reference stable geometry rather than edges that a later cut will consume.