.SDD File Extension
What is an SDD file?
Presentation originally created by StarImpress, a slide show program included in the StarOffice suite; saves a collection of slides, often incorporating a title slide followed by supporting slides.
SDD files were used by StarImpress through version 5. StarImpress version 6 adopted the .SXI format, but now Open Office (StarOffice's successor) and Apache OpenOffice both use .ODP files for presentations.
NOTE: Apache OpenOffice was previously known as OpenOffice.org.