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For information about abbreviations and formatting used in this table, see<br />
“Formatting Conventions in This Reference” on page 6.<br />
Ellipse group codes<br />
Group codes<br />
Description<br />
100 Subclass marker (AcDbEllipse)<br />
10 Center point (in WCS)<br />
DXF: X value; APP: 3D point<br />
20, 30 DXF: Y and Z values of center point (in WCS)<br />
11 Endpoint of major axis, relative to the center (in WCS)<br />
DXF: X value; APP: 3D point<br />
21, 31 DXF: Y and Z values of endpoint of major axis, relative to the center (in<br />
WCS)<br />
210 Extrusion direction (optional; default = 0, 0, 1)<br />
DXF: X value; APP: 3D vector<br />
220, 230 DXF: Y and Z values of extrusion direction (optional)<br />
40 Ratio of minor axis to major axis<br />
41 Start parameter (this value is 0.0 for a full ellipse)<br />
42 End parameter (this value is 2pi for a full ellipse)<br />
The group codes 41 and 42 are the start and end values for u in the equation<br />
describing the Parameter option of the ELLIPSE command (see the following<br />
topic, “ELLIPSE Command’s Parameter Option”). The magnitude of the<br />
codes 11,21,31 vector is equal to 1/2 of the major axis which is the a value in<br />
the equation. The point 10,20,30 is the c value in the equation. Knowing all<br />
these, we can calculate the b value to complete the equation.<br />
ELLIPSE Command’s Parameter Option<br />
The Parameter option of the ELLIPSE command uses the following equation<br />
to define an elliptical arc.<br />
p(u)=c+a*cos(u)+b*sin(u)<br />
The variables a, b, c are determined when you select the endpoints for the<br />
first axis and the distance for the second axis. a is the negative of 1/2 of the<br />
ELLIPSE | 77
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