In additive fabrication, less stiff layers generally require a comparatively higher peel force during separation, and that therefore geometric structures that include less stiff layers will also require a comparatively higher peel force during separation. Techniques to lower or otherwise mitigate undesirably large peel forces are described. These techniques include modification to how layers susceptible to a large peel force are formed, modification to a model of a part prior to generating instructions for an additive fabrication device to fabricate the part, and/or improvements to an additive fabrication device hardware.