TechDraw LengthDimension/ro

TechDraw Dimension Length

Menu location
TechDraw → Dimension Length
Workbenches
TechDraw
Default shortcut
None
Introduced in version
-
See also
None

Descriere

Instrumentul pentru cote tip distanță adaugă o cotă distanță unei imagini. Cota poate fi între două vârfuri, lungimea unei muchii sau distanța dintre două margini. Distanța va fi inițial distanța proiectată(adică așa cum este reprezentată în desen), dar această distanță poate fi înlocuită prin distanța 3D reală utilizând instrumentul Link Dimension .

The TechDraw LengthDimension tool adds a linear dimension to a View. The dimension may be the distance between two points, the length of a straight edge, the perpendicular distance between two edges, or the perpendicular distance between a point and an edge.

Length dimension taken from two points

Cum se folosește

  1. Select the points and/or edges which define your measurement. The geometry may be selected in the 3D view (first two options) or in the drawing (all options):
    • Select two points.
    • Select a single straight edge.
    • Select two edges. If both edges are straight they must be parallel. This will produce a perpendicular dimension if an endpoint of one of the edges has a perpendicular projection on the other edge (the resultant point must lie on the actual edge). If multiple solutions are possible, the endpoint that is closest to its projected point is used. If there is no valid perpendicular projection, the dimension will be the distance between the nearest endpoints of the edges.
    • Select a point and an edge. This will produce a perpendicular dimension. In version 0.21 and below the dimension will only be perpendicular if the point has a perpendicular projection on the actual edge. Else the dimension will be the distance between the point and the nearest endpoint of the edge.
  2. If you have selected geometry in the 3D view: add the correct TechDraw View to the selection by selecting it in the Tree view.
  3. There are several ways to invoke the tool:
    • introduced in version 1.0: If the Dimensioning tools preference is set to Single tool (default): press the down arrow to the right of the button and select the Insert Length Dimension option from the dropdown.
    • If this preference has a different value (and in version 0.21 and below): press the Insert Length Dimension button.
    • Select the TechDraw → Dimensions → Insert Length Dimension option from the menu.
  4. A dimension is added to the View.
  5. The dimension may be dragged to the desired position.
  6. If needed, add tolerances as described on this page.

Display 3D measurement

The dimension will initially display the projected measurement (i.e. as shown in the drawing). If required, and if the dimension is based on 3D references, it can be changed to the actual 3D measurement by changing its DateMeasure Type property to True. To base a dimension on 3D references select geometry from the 3D view at creation time, or use the TechDraw DimensionRepair tool to update existing dimensions.

Change properties

To change the properties of a dimension object either double-click it in the drawing or in the Tree view. This will open the Dimension dialog.

Dimension dialog

The dimension dialog offers the following settings:

Tolerancing

Formatting

Display Style

Lines

Note

Dimension objects are vulnerable to the "topological naming problem". This means that if you modify the 3D geometry, the faces and edges of the model may be renamed internally. If a dimension is attached to an edge that is then modified, the dimension may break. In general, it is not possible to keep the projected 2D dimensions synchronized with the actual 3D objects.

Therefore, it is recommended that dimensions be added when the 3D model is no longer being modified.

Workaround

If you want to keep a TechDraw view with dimensions that won't break, you need to dimension an object that won't change:

See Landmark Dimensions for another approach to circumventing the topological naming issue.

Notes

Proprietăți

Data

Base

True - based on 3D geometry.
Projected - based on 2D drawing View geometry.
false - a common dimension by default, possibly with tolerances.
true - a theoretical value. As such, it shall not bear any tolerances. The dimension will be displayed by a frame around the value:
true - the negated value of the DateOver Tolerance is used as DateUnder Tolerance. The display will be
false - the DateUnder Tolerance is taken into account. The display will be
false - the ordinary value is used. For length it is a positive number, for angle the oblique value (0° - 180°).
true - the inverted value is used. For length a negative number, for angle the reflex value (180° - 360°).

Format

false - the content of the Format Spec is used to format the actual dimensional value.
true - the content of the Format Spec will be displayed as text instead of the dimension value.

Override

false - the directions are computed as usual.
true - the directions are overridden by LineAngle and ExtensionAngle property values.

References

View

Base

Dimension Format

false - Let the direction of arrows to be selected automatically according to the rule above.
true - Override the automatically chosen direction and force the opposite one.
None - no lines or arrows are drawn, only the bare dimension value is displayed.
Minimal - for lengths and angles a single headed line connecting the dimensional value and the end point's virtual extension line is drawn. The extension line itself is not added.
Diameters are rendered following Confined extent, radii following Reduced extent.
Confined - for lengths and angles a double headed line (or arc) connecting the start and end point's virtual extension lines is drawn, though the extension lines themselves are not added.
Diameters are drawn with a minimal single headed line from dimensional value to the closest point on circle, radii as with Reduced extent.
Reduced - for lengths and angles a single headed line connecting the dimensional value and the end point's extension line is drawn along with the extension line itself.
Diameters are drawn with a single headed line from the center to the closest point on circle, radii with a minimal single headed line from dimensional value to the closest arc point.
Normal - the default value. For lengths and angles a double headed line (or arc) connecting the start and end point's extension lines is drawn, the extension lines themselves as well.
Diameters are drawn as double headed lines striking the center and connecting the closest and farthest points on the circle.
Radii are drawn as a single headed line from center to the closest arc point.
Expanded - Only diameters support this value, rendering them in a horizontal or vertical length-like way. Other dimension types are rendered as with Normal extent.
Differences between the supported standards
ISO Oriented - drawn according to the standard ISO 129-1, text is rotated to be parallel with the dimension line tangent.
ISO Referencing - drawn in compliance with ISO 129-1, text is always horizontal, above the shortest possible reference line.
ASME Inlined - drawn according to the standard ASME Y14.5M, text is horizontal, inserted in a break within the dimension line or arc.
ASME Referencing - drawn in compliance with ASME Y14.5M, text is horizontal, short reference line is attached to one side's vertical center.

Script

Cotele tip distanță pot fi adăugate la Pages utilizând Python.

See also: Autogenerated API documentation and FreeCAD Scripting Basics.

The Length Dimension tool can be used in macros and from the Python console by using the following functions:

dim1 = FreeCAD.ActiveDocument.addObject("TechDraw::DrawViewDimension", "Dimension")
dim1.Type = "Distance"
dim1.References2D=[(view1, "Edge1")]
page.addView(dim1)