CAD File Format

• CAD stands for Computer Aided Design.
• File Format may contain 2D or 3D designs.
• These files are generated by CAD Software.
• CAD is used in the creation, modification, analysis or optimization of design.
• Designs the Curves and Figures in 2D Space.
• Designs the Curves, Surfaces and Solids in 3D.

2D :

• By 2D we can only create an image with on side
• If you want to  represent a building elevation design we have to draw four different diagrams.
• But 2D diagrams are useful for drawing an object with perfect measurement.

3D:

• By 3D we can view every side of the image.
• We can recognize easily each and every minute part.
• 3D design makes to know how an object looks directly.

Some of the CAD file extensions:

STEP:

• STEP is the most widely used and most recommended of 3D file Formats. 
• It is an ISO 10303-21 standard.
• Most of the software support STEP importing and exporting.

STL:

• STL stands for Stereo Lithography
• It is the universal format for pure 3D information created by 3D Systems. 
• The biggest problem with STL is that it describes only the surface geometry of a 3D object without any color or texture.
• The STL format specifies both ASCII and binary representations.
• Binary files are more common, since they are more compact.

VRML:

• Virtual Reality Modeling Language
• It is a standard file format for representing 3D interactive vector graphics.
• It carries somewhat more information than STL.

DWG:

• DWG means drawing.
• Supports Both 2D and 3D objects.
• Is a portable software.