Pascal vd Heiden (also known as CodeImp) born on July 15, 1982, is a regular in the Doom community, a developer of notable Doom supporting applications and resource maintainer of Doomworld. For his living, he works at Triumph Studios as technical programmer. Heiden is the creator of the software and services featured at CodeImp, which is his trademark for his personal projects and nickname in the Doom community. He has developed two major Doom related products:
- Doom Connector was a service for online Doom multiplayer with various Doom source ports. Heiden designed and developed this service. This product and support was discontinued on May 30, 2005.
- Doom Builder is a map editor for Doom and various Doom source ports. In August 2003, Heiden started this project as a basic map editor. Later he introduced 3D Mode editing in the Doom editing scene, as popularised by the Duke Nukem Build editor. In January 2008 he announced that the development of Doom Builder 2 (a more high-end rewrite of this tool) has begun. 
In October 2005, ZDaemon project leader Raider accused CodeImp of placing a trojan in a patch purporting to repair a bug in Skulltag. The trojan was downloaded by many members of the Doom gaming community and subsequently used to initiate a Denial of Service attack on the ZDaemon master server. According to Raider, CodeImp took credit for the action, regarding it as a revenge tactic .