AutoCAD Tutorial : Concept of Mirror

You can flip objects about a specified axis to create a symmetrical mirror image.

Mirroring is useful for creating symmetrical objects because you can quickly draw half the object and then mirror it instead of drawing the entire object.

You flip objects about an axis called a mirror line to create a mirror image. To specify this temporary mirror line, you enter two points. You can choose whether to erase or retain the original objects.

When you mirror text, attributes, and attribute definitions, they are reversed or turned upside down in the mirror image. If you want to prevent this, set the MIRRTEXT system variable to 0 (off). Text then has the same alignment and justification as before the mirroring.

MIRRTEXT affects text that is created with the TEXT, ATTDEF, or MTEXT commands; attribute definitions; and variable attributes. Text and constant attributes within an inserted block are mirrored as a consequence of mirroring the entire block. These objects are reversed regardless of the MIRRTEXT setting.

Mirror in 3D
With MIRROR3D, you can mirror objects across a specified mirroring plane. The mirroring plane can be one of the following:

• The plane of a planar object
• A plane parallel to the XY, YZ, or XZ plane of the current UCS that passes through a specified point
• A plane defined by three specified points (2, 3, and 4)

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