File Extension XSI File Format SOFTIMAGE |XSI 3D model XSI stands for SOFTIMAGE |XSI 3D model. This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question Alternative to SQL Cross apply because of performance issues Singapore models entire country in 3D with smart map Sneak Peek: HTC Flyer 2. Is 3D The Way Forward?