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U3D Converter


U3D_Reader supports reading .u3d files (Standard ECMA-363, 1st Edition) in binary format.
U3D_Writer supports writing .u3d files (Standard ECMA_363, 4th Edition, June 2007).


Import Export
  • polygonal representations
  • assembly structure
  • names
  • colors and materials
  • polygonal representations
  • assembly structure
  • names
  • colors


Exporter Parameters

Export parameters are controlled by U3D_WriterParameters.

Parameter Default value Description
LengthUnit() Base_LU_Meters See Base_WriterParameters::LengthUnit().
UseOYAsUpAxis() false Specifies that Y axis should be considered pointing upwards, for downstream usage of the model in software with that convention. By default Z axis points upwards.
See Base_WriterParameters::UseOYAsUpAxis().

Known Limitations


  • U3D models may contain textures but U3D_Reader doesn't read them yet.
  • U3D does not store the unit information. Currently the units are interpreted as meters and the lengths/coordinates are scaled appropriately.


  • Currently only export of colors is available, but not materials. Some software may display exported models without proper shading and/or color. This depends on whether the software in question relies on materials for coloring and shading, or if it can use diffuse mesh colors.
  • The names of the entities in the exported file must be unique. As a result, if there were entities with the same names in the exported model, the sequence number of the entity will be added at the end of the entity name.