MLINE (DXF)

The following group codes apply to mline entities.

Mline group codes
Group code	Description
100	Subclass marker (AcDbMline)
2	String of up to 32 characters. The name of the style used for this mline. An entry for this style must exist in the MLINESTYLE dictionary. Do not modify this field without also updating the associated entry in the MLINESTYLE dictionary
340	Pointer-handle/ID of MLINESTYLE object
40	Scale factor
70	Justification: 0 = Top 1 = Zero 2 = Bottom
71	Flags (bit-coded values): 1 = Has at least one vertex (code 72 is greater than 0) 2 = Closed 4 = Suppress start caps 8 = Suppress end caps
72	Number of vertices
73	Number of elements in MLINESTYLE definition
10	Start point (in WCS) DXF: X value; APP: 3D point
20, 30	DXF: Y and Z values of start point (in WCS)
210	Extrusion direction (optional; default = 0, 0, 1) DXF: X value; APP: 3D vector
220, 230	DXF: Y and Z values of extrusion direction (optional)
11	Vertex coordinates (multiple entries; one entry for each vertex) DXF: X value; APP: 3D point
21, 31	DXF: Y and Z values of vertex coordinates
12	Direction vector of segment starting at this vertex (multiple entries; one for each vertex) DXF: X value; APP: 3D vector
22, 32	DXF: Y and Z values of direction vector of segment starting at this vertex
13	Direction vector of miter at this vertex (multiple entries: one for each vertex) DXF: X value; APP: 3D vector
23, 33	DXF: Y and Z values of direction vector of miter
74	Number of parameters for this element (repeats for each element in segment)
41	Element parameters (repeats based on previous code 74)
75	Number of area fill parameters for this element (repeats for each element in segment)
42	Area fill parameters (repeats based on previous code 75)

The group code 41 parameterization is a list of real values, one real per group code 41. The list may contain zero or more items. The first group code 41 value is the distance from the segment vertex along the miter vector to the point where the line element's path intersects the miter vector. The next group code 41 value is the distance along the line element's path from the point defined by the first group 41 to the actual start of the line element. The next is the distance from the start of the line element to the first break (or cut) in the line element. The successive group code 41 values continue to list the start and stop points of the line element in this segment of the mline. Linetypes do not affect group 41 lists.

The group code 42 parameterization is also a list of real values. Similar to the 41 parameterization, it describes the parameterization of the fill area for this mline segment. The values are interpreted identically to the 41 parameters and when taken as a whole for all line elements in the mline segment, they define the boundary of the fill area for the mline segment.

A common example of the use of the group code 42 mechanism is when an unfilled mline crosses over a filled mline and mledit is used to cause the filled mline to appear unfilled in the crossing area. This would result in two group 42s for each line element in the affected mline segment; one for the fill stop and one for the fill start.

The 2 group codes in mline entities and mlinestyle objects are redundant fields. These groups should not be modified under any circumstances, although it is safe to read them and use their values. The correct fields to modify are as follows:

Mline

The 340 group in the same object, which indicates the proper MLINESTYLE object.

Mlinestyle

The 3 group value in the MLINESTYLE dictionary, which precedes the 350 group that has the handle or entity name of the current mlinestyle.