Ray Dream
From Just Solve the File Format Problem
Ray Dream Designer / 3D / Studio is 3D graphics software. Developed for the Macintosh in 1989, sold to Fractal in 1996, then to MetaTools/MetaCreations, merged with Infini-D and is now Carrara.[1][2]
File Identification
Ray Dream files can have extensions .RD4 for version 4 and .RDS.
Corel licensed the software around 1996 and bundled Corel Dream3D with its CorelDRAW suite, starting with version 6. Corel Dream3D files have the .D3D. extension but are the same file format.[3]
All files have the header "33444320
" or "3DC " in ascii. Followed by the software and version which produced the file. ie. "Ray Dream Designer(R) 3.0" or "Ray Dream Studio(TM) 5"