What is a DWG and DXF file?

in #techreview8 years ago

DWG File Format

  • This is the AutoCAD drawing file format
  • AutoCAD is the drawing/design software similar to MicroStation but developed by Bentley’s competitor Autodesk.
  • DWG file names must contain the file extension .dwg

DXF File Format

  • The DXF file format is an ASCII text representation of the DWG format.
  • DXF is an interchange format historically used to exchange data between AutoCAD and other applications.

Understanding the DWG File Format

DWG Units

Unitless System – The element information is stored in the DWG file as Drawing Units. There is no linear unit associated with the elements. Element coordinates and lengths are in drawing units.

Unit display format – DWG files use the per drawing setting LUNITS to determine how lengths are used displayed. There are five valid unit display settings.
1 = Scientific 3.025E+01
2 = Decimal 30.25
3 = Engineering 2’-6.25”
4 = Architectural 2’-6 ¼”
5 = Fractional 30 1/4

Design Center Units (Insertion Scale) - Controls the unit of measurement for blocks and drawings that are inserted into the current drawing. This can be set to Unitless.

Models

  • Only supports one Design Model and multiple Sheet Models
  • Does not support Drawing Models
  • Can not rotate a sheet model

Reference Attachments

  • Can only reference the Design Model. Can not reference Sheet Models
  • The active model can not be self referenced
  • All references are Live nested
  • Nest depth is not supported. The nest depth is infinite.