The upper half is for additional information, such as dimensions of the datum target area. You may use this domain in literature without prior coordination or asking for. The letter represents the datum feature, and the digit represents the datum target number. This domain is for use in illustrative examples in documents. The lower half is for a letter and a digit. The datum dialog opens and you can change the label. Datum targets are circular frames divided in two parts by a horizontal line. A datum feature, on the other hand, is the physical representation of datum. The datum is an imaginary but theoretically perfect surface, line, or points. To change the label, click to select the datum, then double-click in the highlighted square: The datum feature, datum, and datum target are the important geometric dimensioning and Tolerancing (GD&T) concept for creating and manufacturing a model.You can associate a datum with a dimension extension line:.

See Callout (Balloon) for more information. You can drag a datum closer to or farther away from its placement point on the drawing and the extension line adjusts appropriately.You can drag a datum to another location after placement: click to select it, then drag.Styling a datumĬlick on the datum you want to style, then click the Styles panel icon on the right side of the page:Įdit the Font, Text height, Color, and Datum size: Consequently, datum feature B is no longer part of the location equation the maximum material boundary of datum feature D is 1.005, which is the virtual condition of datum feature D with respect to datum feature A. These are inferencing lines that you are able to align the dimension to simply click when you see the line appear to align the dimension to that line. The datum translation symbol allows datum feature D to translate with respect to datum feature B. A leader line can also be used to connect the datum feature symbol to the view in some applications.While moving the mouse, you'll notice thin, red, dashed lines as the cursor passes near other entities. When a surface is designated as a datum feature on a part, the datum feature symbol is placed on the edge view of the surface or on an extension line in the view where the surface appears as a line. Tangent plane: A plane that contacts the high points of the specified feature surface. (For more information regarding Datum Feature Symbol placement, see our Datum Feature Symbol page. Because of how the datum feature symbol is placed, we know that it is referencing the surface which results in a planar datum. The leader line can be shown as a dashed line if the datum feature is not on the visible surface. Datum Feature A is the bottom surface indicated on the front view of the drawing that is being controlled by flatness. The datum feature symbol can also be placed on a leader line directed to the surface.

You can connect a leader to GD&T symbols. The datum feature symbol is placed on the edge view or on an extension line in the view where the surface appears as a line. This is the primary method for adding feature control frames, geometric tolerancing symbols, and datum feature symbols. Symbol Description Datum targets are circular frames divided in two parts by a horizontal line. In order to specify practical data, relevant locations called datum targets can be selected and indicated on a drawing. Methods for placing datum feature symbols on datum feature surfaces. It can be impractical to use a datum to control the tolerance of an entire surface, as the datum establishes a theoretically exact plane, line, or profile. And succeeding the above should be written the symbols of location by which the point is located in space with reference to the datum - planes of the system. Chapter 3 Datums 81 Angled Surface Datum feature symbol placed on edge view of surface or extension line from edge view Surface datum feature symbols must be clearly separated from dimension line arrowheads The Drawing The Meaning The Drawing The Meaning Example 3-3.

Datum symbol