VisionArt
VisionArt was a company created back in blah blah that did some of the very first work on the Defiant and other ships for DS9.
Industrial Lights & Magic
Technically the CG model used by ILM was borrowed from VisionArt, but ILM did modify it for the Defiant's feature film debut.
Digital Muse
Every year computer graphics got better and better so upgrading the ship model, or creating new ones was necessary.
EdenFX
Every year computer graphics got better and better so upgrading the ship model, or creating new ones was necessary.