cdsl-cad/backend/agent/skills/cad-engine/references/part-skills/source/atomic/extrude-base-profile.atomic.md

Extrude Base Profile Atomic Skill

When to use

• The first solid body is a simple prismatic shape made from a closed 2D profile: rectangle, rounded rectangle, circle, annulus, hexagon, or simple contour.
• The part is a plate, block, simple cylinder, bracket base, washer blank, spacer blank, or nut body made by extrusion.

Do not use when

• The primary body has multiple coaxial diameter steps better made by revolve.
• The shape is freeform, lofted, swept, bent sheet metal, or surface-based.
• The extrusion profile is open or ambiguous.

Recognition features

• SolidWorks evidence such as Extrusion/Boss-Extrude after a single sketch.
• STEP evidence dominated by planar faces for prismatic parts or cylindrical surfaces for simple cylinders.
• Descriptions mention rectangular block, plate, simple cylinder, extruded profile, or uniform thickness.

Core invariants

• Start from a fully closed, constrained sketch.
• Extrude normal to the sketch plane by the intended thickness or length.
• Use symmetric or mid-plane extrusion when the part should stay centered on a datum.
• Keep the base body simple; add holes, pockets, bosses, slots, and edge treatments as later features.
• Use concentric circles for annular extrusions such as washers or tubes.

Parameter roles

• profile_type selects rectangle, circle, annulus, hexagon, or custom closed contour.
• length, width, radius, outer_radius, inner_radius, and across_flats define the sketch.
• extrude_depth or thickness defines the solid depth.
• extrude_direction and midplane define placement relative to datums.

Construction sequence

1. Select the reference plane or face for the base profile.
2. Draw and constrain the closed profile.
3. Apply dimensional constraints for width, length, radius, or diameter.
4. Extrude the profile to the required depth.
5. Keep the resulting body merged as the main solid unless separate bodies are explicitly requested.
6. Add secondary cuts and edge treatments afterward.

Common failures

• Using an open sketch for solid extrusion.
• Combining holes and detailed cutouts into the first sketch when separate features would be clearer.
• Using multiple separate extrusions for what should be one base body.
• Extruding a stepped shaft when revolve would preserve axial intent better.

Evidence summary

• Latest run evidence: 70 accepted atomic insights matched base extrusion from rectangular/circular profiles.
• Strong repeated names include extrude_rectangle, extrude_circle, extrude_rectangle_from_sketch, extrude_rectangular_profile, and extrude_circular_profile.
• Frequent operations in the latest run: Extrusion, Sketch, Cut, Chamfer.
• Source model examples: 000166, 026303, 050972, 053267, 088851, 114800, 148444, 157630, 162045, 188147, 209994, 220726, 237160, 238926.
• Source: CAD-SkillX offline review of SCAD58 descriptions, STEP summaries, and SolidWorks feature evidence.

Retrieval metadata

Triggers:

• extrude base profile
• extrude rectangle
• extrude circle
• base extrusion
• simple cylinder
• rectangular block

Secondary triggers:

• plate blank
• bracket base
• washer blank
• annular extrusion
• uniform thickness

Operation triggers:

• sketch closed profile
• boss extrude
• extrude to thickness
• midplane extrusion

Exclusions:

• stepped shaft
• revolve profile
• loft
• sweep
• sheet metal bend