Terminology in drafting — definition of a fillet feature A “fillet” is a rounded surface applied to which corner condition of a part in technical drawings and CAD models?

Introduction / Context:
Fillets and rounds are standard edge treatments used to remove sharp corners and reduce stress concentrations. Correctly naming them avoids confusion in design, machining, and inspection. CAD tools also separate “fillet” and “round” features based on corner type.

Given Data / Assumptions:

• Fillet applies to an internal (inside) corner between two surfaces.
• Round applies to an external (outside) corner.
• Both are typically dimensioned by radius.

Concept / Approach:
An inside corner fillet smooths the intersection of surfaces, improving flow (fluids or stress), enabling tool access, and preventing crack initiation. Manufacturing processes (milling, casting, injection molding) often require minimum internal radii due to tool geometry or mold release limits.

Step-by-Step Solution:

Verification / Alternative check:
Check a CAD system (Fillet feature) on the internal edge between two faces; the software adds a concave radius at the inside corner, confirming the definition.

Why Other Options Are Wrong:

• Outside: describes a round, not a fillet.
• Radial: nonspecific; both fillets and rounds have radii.
• Isoplane: relates to isometric drafting modes, not geometry features.
• Edge blend regardless of type: imprecise for manufacturing documentation.

Common Pitfalls:

• Omitting a radius value, which leaves the feature undefined for production.

Final Answer:
Inside