GD&T · Profile · ASME Y14.5
Profile of a Line GD&T Symbol — Meaning and Datum Rule
https://shopmath.org/gdt/profile-of-a-line · data verified August 1, 2026
Profile of a Line (⌒) is a GD&T profile control, and its tolerance zone is two curves offset from the true profile, in each cross-section. It may be used with or without a datum.
- Symbol
- ⌒
- Unicode
- U+2312
- Category
- Profile
- Datum
- optional
Profile of a Line · GD&T profile symbol
⌒
- Unicode
- U+2312
- Datum
- optional
- Zone
- Two curves offset from the true profile, in each cross-section
The value in the feature control frame is the width or diameter of that zone, in the drawing's units.
What Profile of a Line Controls in GD&T
Controls the shape of a cross-sectional outline against its theoretically exact geometry. The zone is two-dimensional and applies section by section, which makes it the right control for extrusions and swept shapes where each slice matters but the whole surface need not be held.
The Profile of a Line GD&T Symbol, Zone and Datum Rule
The symbol as it appears in the feature control frame, with the codepoint to type it and the rule it carries.
| Property | Value |
|---|---|
| Symbol | ⌒ |
| Unicode codepoint | U+2312 (ARC) |
| Category | Profile controls — Control a surface or outline against its theoretically exact geometry. |
| Tolerance zone | Two curves offset from the true profile, in each cross-section |
| Datum reference | May be applied with or without a datum. Without one it controls the feature's own shape; with one it also controls where that shape sits. |
| Standard | ASME Y14.5 (cited, not reproduced); ISO 1101 |
| Also called | line profile |
The symbol character is the Unicode codepoint used in drawings and CAD annotations; drafting standards render it with defined proportions that the font approximates.
Sources and Method for the Profile of a Line GD&T Reference
- Profile of a Line symbol and rulescompiled
Symbols and codepoints: Unicode Character Database (Unicode License v3). Characteristic list cross-checked against NASA MSFC GD&T Basics (public domain). Descriptions written from scratch; no ASME Y14.5 text reproduced.
Verified against Unicode Character Database codepoint check; 98/98 structural checks passed
Compiled from independent public sources that agree cell-for-cell.
- Assumptions
- The standard is cited, never reproduced: no ASME Y14.5 definitional text, worked example or figure appears on this site. The description above is original prose.
- ASME Y14.5 and ISO 1101 differ in places — the ISO system uses the envelope requirement differently and does not carry every ASME modifier. Where a drawing names a standard, that standard governs.
- Dataset scope: EXCLUDED: all ASME Y14.5 definitional text, worked examples and figures. Every description on this site is original prose.
- Data last verified
- August 1, 2026
How to Cite This Profile of a Line GD&T Reference
Citation
ShopMath. "Profile of a Line GD&T Symbol — Meaning and Datum Rule." ShopMath, verified August 1, 2026, https://shopmath.org/gdt/profile-of-a-line
BibTeX
@misc{shopmath-gdt-profile-of-a-line,
title = {Profile of a Line GD&T Symbol — Meaning and Datum Rule},
author = {{ShopMath}},
year = {2026},
howpublished = {\url{https://shopmath.org/gdt/profile-of-a-line}},
note = {Data verified 2026-08-01}
}Permanent URL
https://shopmath.org/gdt/profile-of-a-line
Common Questions About Profile of a Line in GD&T
What does Profile of a Line mean in GD&T?
- Controls the shape of a cross-sectional outline against its theoretically exact geometry. The zone is two-dimensional and applies section by section, which makes it the right control for extrusions and swept shapes where each slice matters but the whole surface need not be held.
What is the Profile of a Line symbol in GD&T?
- ⌒ — Unicode U+2312 (ARC). It goes in the first compartment of the feature control frame, ahead of the tolerance value.
Does Profile of a Line need a datum?
- May be applied with or without a datum. Without one it controls the feature's own shape; with one it also controls where that shape sits.
What shape is the Profile of a Line tolerance zone?
- Two curves offset from the true profile, in each cross-section. Every point of the controlled feature has to lie inside that zone for the part to pass.
Which GD&T controls are in the same group as Profile of a Line?
- Profile of a Line is one of 2 profile controls: Profile of a Line, Profile of a Surface.