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    by Dennis Collin

    ACAD_control_linetype_DC_01.jpg

    ACAD_control_linetype_DC_02.jpg

    Fig. Linetypes not showing or behaving strangely? Read on!

    Misbehaving linetypes are a common issue for many AutoCAD users. The most common issue is the mis-setting of AutoCAD variables and, or not fully understanding, AutoCAD’s not so new annotative scaling feature.

    I have written a post on the numerous ways of controlling linetype scaling issues here:

    https://www.cadlinecommunity.co.uk/hc/en-us/articles/360001921997-AutoCAD-Controlling-the-appearance-of-linetypes-in-drawings

    Another problem is the alignment of linetypes symbols particularly when using a text string to describe for example,  linework describing a pipe network or other kind of service.

    For older versions of AutoCAD depending upon how the line is drawn, annotation could sometime appear upside down. Whilst there is a reverse command, this is not always desirable since the direction of line may matter when being considered for network analysis like AutoCAD MAP.

    The key is understanding the switches in the linetype definition file and the alignment options that can be set. In the sample image above, we have 3 lines where the annotation behaves differently. In most circumstances the topmost option is the desired outcome!

    Looking at the linetype file below the key reference is the entry after the size (s=1.3,..)

    The rotation angle of the characters to be displayed in the linetype. The rotation angle must be prefixed with either a “U=..”, “R=..” , or “A=..”. Usually the default angle, whatever the orientation is zero.

    “U”:specifies upright or right-reading text. (this option is usually the preferred default)

    “R”;specifies relative or tangential rotation with respect to the line position. (this option can be useful, if the line direction is important)

    “A”;specifies absolute rotation of the text with respect to the origin; that is, all text has the same rotation regardless of its position relative to the line.

    ACAD_control_linetype_DC_03.jpg

    Fig. Custom AutoCAD linetype file with each of the rotation behaviours defined.