Free tools for hollow bed adhesion 3D models mainly include open-source slicers like PrusaSlicer, Cura, and SuperSlicer.
These tools let you adjust bed adhesion settings—such as brims, rafts, or skirts—to fix warping/lifting in hollow models, which have thin walls and less surface contact with the bed. PrusaSlicer lets you tweak brim width, Cura has preset "Adhesion" options, and SuperSlicer adds finer control for thin-walled parts.
If your hollow model still lifts, try increasing the brim width by 5–10mm in these slicers. It spreads adhesion evenly without extra weight, helping the model stay put during printing.