GD&T · Profile · ASME Y14.5
Profile of a Surface GD&T Symbol — Meaning and Datum Rule
https://shopmath.org/gdt/profile-of-a-surface · data verified August 1, 2026
Profile of a Surface (⌓) is a GD&T profile control, and its tolerance zone is two surfaces offset from the true profile. It may be used with or without a datum.
- Symbol
- ⌓
- Unicode
- U+2313
- Category
- Profile
- Datum
- optional
Profile of a Surface · GD&T profile symbol
⌓
- Unicode
- U+2313
- Datum
- optional
- Zone
- Two surfaces offset from the true profile
The value in the feature control frame is the width or diameter of that zone, in the drawing's units.
What Profile of a Surface Controls in GD&T
The most general control in the system: a three-dimensional band around the theoretically exact surface that the actual surface must stay inside. Referenced to datums it locates and orients the surface as well as controlling its form, which is why it can stand in for flatness, position, and orientation on a single feature.
The Profile of a Surface 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+2313 (SEGMENT) |
| Category | Profile controls — Control a surface or outline against its theoretically exact geometry. |
| Tolerance zone | Two surfaces offset from the true profile |
| 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 | surface 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 Surface GD&T Reference
- Profile of a Surface 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 Surface GD&T Reference
Citation
ShopMath. "Profile of a Surface GD&T Symbol — Meaning and Datum Rule." ShopMath, verified August 1, 2026, https://shopmath.org/gdt/profile-of-a-surface
BibTeX
@misc{shopmath-gdt-profile-of-a-surface,
title = {Profile of a Surface GD&T Symbol — Meaning and Datum Rule},
author = {{ShopMath}},
year = {2026},
howpublished = {\url{https://shopmath.org/gdt/profile-of-a-surface}},
note = {Data verified 2026-08-01}
}Permanent URL
https://shopmath.org/gdt/profile-of-a-surface
Common Questions About Profile of a Surface in GD&T
What does Profile of a Surface mean in GD&T?
- The most general control in the system: a three-dimensional band around the theoretically exact surface that the actual surface must stay inside. Referenced to datums it locates and orients the surface as well as controlling its form, which is why it can stand in for flatness, position, and orientation on a single feature.
What is the Profile of a Surface symbol in GD&T?
- ⌓ — Unicode U+2313 (SEGMENT). It goes in the first compartment of the feature control frame, ahead of the tolerance value.
Does Profile of a Surface 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 Surface tolerance zone?
- Two surfaces offset from the true profile. 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 Surface?
- Profile of a Surface is one of 2 profile controls: Profile of a Surface, Profile of a Line.