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- create-linear-dimension-2015.fmw
Introducing AutoCAD Dimensions
Dimension features in AutoCAD are defined using format attributes, rather than creating geometry. However, the dimension must be an aggregate of at least one feature, although that feature needs no geometry. There are a large number of format attributes for AutoCAD dimension features, but not all are necessary to create valid dimensions. Since linear dimensions are the most commonly converted form, we have started with them. Other dimension types will be added as we determine the minimal attributes to create them. If you do need to create a dimension not described on this page, please Contact Technical Support.
Example 1: Creating Linear Dimensions
The attached workspace Create_Linear_Dimension.fmw is a simple workspace which shows how to create a linear dimension from scratch. The formats attributes specific to geometry are shown below, along with a snapshot of the workspace. Notice how an aggregate feature is created with a number of dimension-related format attributes.
Linear Dimension Geometry Diagram
Diagram of the attributes controlling the dimension geometry
Sample workspace to create a linear dimension
Dimension Attributes
Along with the format attributes that set the geometry, a number of other format attributes are required that describe text, dimension nostyle and type. The following are the minimal format attributes that must be present on the feature to create a linear dimension:
autocad_defpt2.x, autocad_defpt2.y, autocad_defpt2.z - The location of the first dimension point. This point should be along the distance being dimensioned
autocad_defpt3.x, autocad_defpt3.y, autocad_defpt3.z - The location of the second dimension point. This should also be along the distance being dimensioned.
autocad_line_defpoint.x, autocad_line_defpoint.y, autocad_line_defpoint.z - The location of dimension line start. This defines the offset of the dimension line and text from the distance being dimensioned.
autocad_text_midpoint.x, autocad_text_midpoint.y, autocad_text_midpoint.z - The location of the text midpoint. This value can be used to position the text along the dimension line, but only takes effect if the autocad_dim_flag is greater than 127.
autocad_dimension_attach_point - The justification of the dimension text
autocad_dimension_type - The type of dimension(still required even if dim_flag below is set):
- autocad_rotated
- autocad_aligned
- autocad_angular
- autocad_diameter
- autocad_radius
- autocad_angular3Pt
- autocad_ordinate
- autocad_xordinate
autocad_dim_flag - The type of dimension (this overrides autocad_dimension_type, but is necessary for a user defined text location):
- 0 = Rotated, horizontal, or vertical
- 1 = Aligned
- 2 = Angular
- 3 = Diameter
- 4 = Radius
- 5 = Angular 3 point
- 6 = Ordinate
- 32 = Indicates that the block reference (group code 2) is referenced by this dimension only.
- 64 = Ordinate type. This is a bit value (bit 7) used only with integer value 6. If set, ordinate is X-type; if not set, ordinate is Y-type.
- 128 = This is a bit value (bit 8) added to the other group 70 values if the dimension text has been positioned at a user-defined location rather than at the default location.
autocad_dimension_style_name - The style to use for dimension
autocad_orig_dim_text - Setting this attribute will override AutoCAD's measurement of the dimension. You can use any string, so you can add prefixes or suffixes to your values if desired.
autocad_entity - This must be set to autocad_dimension