1. DXF文件需保存为autocad R12/R14格式，并将spline映射为2D-polyline
2. 如果是在已有的PCB设计基础上导入新的DXF信息，需要勾选incremental addition
3. 对导入的DXF闭合多边形使用Z-copy命令时碰到“Not a closed polygon or CLine”时
1> import dxf file into a unused class/subclass first
2> use Shape-Compose Shape check the options tab and select the right class/subclass for the shape (in this case, class-Board geometry, subclass-outline), then select the imported dxf data,
and you get a composed shape on the class/subclass that you just specified.
3> you might need to delete the imported dxf data afterwards.