Csm edit
The Chasm Level Editor came with the retail CD version of Chasm: The Rift. It allows for editing and creating levels. No user content made with this editor has been found online, however.

The level editor allows editing of a level's walls, ceilings, floors, lights, ambient sounds, objects, links, and processes.

When creating a new level, the editor gives a choice of three different themes: Techno, Egypt, and Medieval.

The editor has a preview box at the upper right of the screen for displaying graphics. The box displays the appearance of any selected textures, objects, and monsters.