Japanese Automotive Manufacturers Association Iges Subset, JAMAIS is a file format subset to IGES. JAMAIS has the same.igs extension and has exactly the same file structure as the IGES format, it only supports less entities.

JAMA-IS:

• does not include Dimensions
• supports only a limited number of entities, optimized for the use in the car-manufacturing.
• does not have the Surface Type option
• does not have vendor tuned settings

The disadvantage of not supporting the above entities is that you can't put all the different elements from an IGES file into Alias. The advantage is that because of the limited elements, there are fewer errors made when translating, everything is optimized for the exchange of the specific models.