DXF

DXF is a file format to exchange CAD data from Autodesk. A DXF file is subdivided in several sections. The most important sections are:

• HEADER
• TABLES, containing definitions of layers
• ENTITIES: containing 2 and 3 dimensional shapes
• BLOCKS: containing 2 and 3 dimension shapes, reusable using INSERTS in ENTITIES.

ENTITIES

Currently, the following Autodesk CAD entity types are supported:

• LWPOLYLINES (2 dimensional line strings), including bulges.
• LINE (single lines).
• POLYLINE (3 dimensional line strings), currently only interpreted as 2 dimensional. The z-coordinate is ignored. See also AutoCAD Documentation.
• HATCH (polygonal data constructed using other boundary entities)
• CIRCLE: full and partial circles, given a center point, radius and start and end angle.
• ELLIPSE: full and partial ellipses, given a center point, major and minor axis, rotation and start and end angle.
• ARC: curved lines given a center point and a radius.
• VERTEX: 2 dimensional point.
• POINT: Same as vertex, but 3 dimensional. Currently only interpreted as 2 dimensional. The z-coordinate is ignored.
• SPLINE: 2 dimensional Control point splines are currently supported.
• INSERT: Predefined BLOCKS inserted at a point and with a rotation and a scale.

BLOCKS

BLOCKS are parts in a CAD drawing that can be reused multiple times by inserting them at different locations with optional alternative rotations and scales. The usage of BLOCKS in a DXF is supported.