refmanualEngineering, within reach.

Geometric requirements

A boxed basic dimension gives a theoretical target

The boxed value identifies theoretically exact target geometry. It is not an ordinary ± size tolerance; the associated requirements establish permitted variation.

Sources and scope ↓

Read beyond the box

Locate the associated geometric control, applicable size limits, datum references and governing edition. ASME basic-dimension and ISO theoretically-exact-dimension terminology should be read in their own systems.

Drawing and model authority

Use the controlled product definition to resolve drawing/model precedence. The presence of a CAD model does not automatically make it authoritative over every drawing requirement.

Continue your task

True position is the target, not the tolerance zone →Separate the datum feature, simulator and datum →Find the geometric control on your drawing →

All tolerance and surface references →

Sources and review scope

Reviewed 23 October 2026. Arithmetic examples are labelled separately from source-table facts and standard scope.

KEYENCE — GD&T drawings and symbols

Manufacturer teaching: control groups, profile with/without datum relationships and theoretically exact dimensions. Not an exhaustive ASME 2018 symbol table.

Open the original source ↗
ASME Y14.5-2018 (R2024)

Public standard catalogue and scope. Full clauses are not reproduced or independently audited here.

Open the original source ↗
ISO 1101:2017

Public scope for geometrical-specification symbols and interpretation. Do not substitute it for ASME drawing rules.

Open the original source ↗