5.2 Extrude Cut Strategies

5.2 Extrude Cut Strategies

Quick Answer: Extruded Cut removes solid material along a sketch profile. Use Through All for holes/slots that pierce the part; use Blind (or geometry-driven ends) for pockets with a floor. End conditions mirror Extruded Boss/Base. Always cut into the existing solid from the sketch plane, verify the preview removes the intended volume, then recompute mass after any depth or diameter change.

If Extruded Boss/Base builds the bulk of a CSWA part, Extruded Cut carves the functional details: mounting holes, slots, pockets, windows, and clearance openings. Wrong cut strategy is one of the fastest ways to fail a mass question: a hole that is only 5 mm deep in a 20 mm plate leaves a huge plug of material; a cut that does not go through leaves volume the exam key assumes is gone.

Cut vs boss: same PropertyManager logic

Start Features → Extruded Cut with a sketch that defines the removal cross-section (circle for a round hole, slot for an elongated hole, closed pocket outline for a cavity). The PropertyManager end conditions are conceptually the same family you learned for bosses:

You still set direction reverse, optional draft on the cut walls, and you still need a valid contour. Cuts do not use “Merge result” the same way bosses do—they subtract from bodies they intersect (scope options can limit which bodies in multibody parts).

Through All vs Blind for holes and slots

Through All — preferred for true through features

When the drawing shows a hole or slot open on both sides of a plate:

• Prefer Through All (or through both directions if the sketch is not on an outer face).
• Benefit: if the exam later changes plate thickness from 10 mm to 15 mm, the hole still pierces. A Blind cut of 10 mm would become a blind hole after the plate thickens—silent mass error.
• Through All also avoids retyping depth when you are unsure of exact thickness during a rushed rebuild.

Blind — required when a floor must remain

Pockets, blind holes (if not using Hole Wizard), and recesses need Blind depth or a face-driven end:

• Match the section-view depth exactly.
• Direction must point into the material that should be removed.
• After modifications to overall thickness, re-read whether pocket depth stays fixed (often yes) while remaining wall thickness changes.

Direction from the sketch plane

Cuts start at the sketch plane and travel in Direction 1 (and optional Direction 2).

Sketch on the face you are cutting from when possible:

1. Select the face → Sketch → draw the hole/slot → Extruded Cut → Through All into the part.
2. Confirm the cut arrow points into the solid. If the preview shows no removal, reverse direction.
3. If you sketched on a plane outside the body (offset plane), you may need Blind depth long enough to reach and pass through the solid, or Through All if the direction aims through the body—preview is mandatory.

Common exam failure mode: Sketch on the top face of a block, extrude cut upward (away from the solid). Feature may fail or remove nothing meaningful. Reverse so the arrow enters the volume.

Midplane sketches: For a hole whose sketch sits on a midplane, use Through All in both directions (or Mid Plane cut with sufficient total depth / dual through options) so both halves of the part open. One-sided Through All only clears one side of the midplane.

Geometry-driven cuts under modification

CSWA intermediate and advanced parts change sizes after the base model exists. Geometry-driven cuts protect intent:

• Up To Surface pocket floor: when a boss height changes the internal cavity layout, selecting the actual floor face keeps pocket depth correct relative to that face.
• Offset From Surface: “leave 3 mm wall under the pocket” can be modeled as cut offset from the bottom face rather than Blind calculated from the top—then base thickness changes still preserve the 3 mm wall if the offset reference is the bottom.
• Up To Next: quick when there is a single unambiguous floor; risky when ribs or extra faces intervene—then the cut stops too soon.

Blind remains best when the problem statement gives a fixed pocket depth that should not track another face.

Multiple contours and internal islands

A single sketch can contain an outer profile and inner islands (for example, a large cut with a post left in the middle—more often a boss workflow—or multiple hole circles in one sketch). For cuts:

• Multiple disjoint hole circles in one sketch can become one Extruded Cut feature (efficient on the exam).
• Use Equal relations and one diameter dimension so a modification “all holes to Ø10” is one edit.
• If Contour Select is active and you only select one circle, only one hole cuts—verify the feature scope in the PropertyManager (Selected Contours).

Cut order and parent-child awareness

Feature order matters:

• Cut after the material you need to remove exists. Cutting before a boss is added cannot remove that future boss’s material.
• Fillets and chamfers on hole edges usually come after the cut (or use Hole Wizard with head conditions—later chapter).
• If a cut fails after a modification, an upstream face used for Up To Surface may have been consumed or moved—edit the cut reference or roll back to diagnose.

Draft on cuts (brief)

Draft while cutting tapers the pocket or opening walls. Section views with angled pocket sides may expect draft on the cut. As with bosses, draft changes removed volume: a drafted pocket removes less or more material than a straight Blind of the same maximum depth depending on inward/outward settings. Match the drawing; do not assume vertical walls if the section shows taper.

Through cuts vs Hole Wizard (exam choice)

Simple Ø through-holes on CSWA are often circle sketch + Extruded Cut Through All. Hole Wizard is preferred when the problem shows standard hole types (counterbore, countersink, tap callouts) with cosmetic threads or standard sizes—covered in a later chapter. Do not fight the drawing: if only a diameter on a plate is shown, Extruded Cut is enough and faster under time pressure.

Mass-property checklist after every cut

1. Preview: translucent removal matches every hole/slot/pocket on the sheet.
2. Section view (in software) or rotate model: confirm through features are open both sides when required.
3. FeatureManager: cut shows correct end condition name and depth/reference.
4. Apply material; Mass Properties after rebuild.
5. After exam modifications (thickness, hole Ø, pocket depth), rebuild and re-check that Through All still pierces and Blind depths still match the new instructions.

Worked strategies

Strategy A — Plate with 4 mounting holes: Sketch four circles on the top face (or one circle + linear pattern later). One Extruded Cut, Through All. Modification to thickness: no cut edit needed. Modification to hole Ø: edit sketch diameter (or pattern seed).

Strategy B — Pocket in a block: Sketch rectangle on top face. Extruded Cut Blind 8 mm (drawing depth). If the exam then increases block height but keeps pocket depth 8 mm, Blind stays; remaining floor thickens. If the exam instead says “pocket through to 5 mm above bottom,” remodel as Offset From Surface from the bottom face by 5 mm so intent survives height changes.

Strategy C — Slot from midplane: Centerline slot on Right plane Mid Plane sketch. Extruded Cut Through All both directions (or appropriate dual-direction through) so the slot opens on both sides of the part.

Traps that destroy CSWA answers

Extruded Cut is not a different language from Extruded Boss—it is the same end-condition toolkit aimed at subtraction. Choose Through All when the drawing is open both sides; choose Blind or face-driven ends when a floor must remain; always verify direction from the sketch plane into the solid before you trust mass properties.