Techniques for releasing parts in additive fabrication and related systems and methods

A build platform for an additive fabrication device, the build platform comprising:

• a rigid structure;
• and
• an actuation structure coupled to the rigid structure, the actuation structure comprising a flexible sheet and two handles coupled to the flexible sheet,
• wherein a first surface of the flexible sheet provides a build surface on which the additive fabrication device is configured to form layers of material, and
• wherein the two handles are configured to be actuated by moving the two handles relative to one another, thereby causing at least part of the flexible sheet to deform away from the rigid structure.

A build platform for an additive fabrication device, the build platform comprising:

• a rigid structure formed from, or comprising, one or more magnets;
• and
• an actuation structure comprising a ferromagnetic flexible sheet and two handles coupled to the flexible sheet, wherein a first surface of the flexible sheet provides a build surface on which the additive fabrication device is configured to form layers of material,
• wherein, in a first configuration of the build platform, the flexible sheet is magnetically coupled to the rigid structure, and
• wherein the two handles are configured to be actuated by moving the two handles relative to one another, thereby producing a second configuration of the build platform in which at least part of the flexible sheet is deformed away from the rigid structure.