According to a pretty good source* on the net-"All special effects for Babylon 5 are computer generated imagery (CGI).
For the first three seasons, the effects were done by Foundation Imaging,
headed by Ron Thornton, utilizing Lightwave 3D and specialized software to
design and render the visual effects. (Lightwave is now running on PCs;
Amigas were used originally.) Macintoshes and PCs are used occasionally
for 2-D effects and painting packages. Starting in season 4, the effects
are done in-house at Netter Digital, using similar equipment to Foundation's".
Maybe Bryce was used as one of the "specialized software' apps.

*http://www.midwinter.com/b5/babylon-5-faq