Due to physical limitations, models with solid cross-sections cannot be printed with UDP mode. Fully enclosed shapes will also start producing problems past a certain height. Hollow objects with a vertical release slot are recommended. For models that require solid infill, natural peel mode is recommended.

Note: Tall enclosed structures would impose a complicated resin level effect and cause deteriorated inner surface and eventually damage the wall, resulting in unwanted thin walls or holes, this applies to all top-down continuous SLA technologies. For any enclosed structures, resin inside will be trapped since the structure wall forbid resin from flowing into or out of the wall. To build the walls continuously, UDP mode consumes resin from both inside and outside of the wall. The resin level inside will drop significantly faster than outside and depletes quickly. Once depleted, the walls will be broken either by insufficient inside resin or by the pressure from outside resin (if the outside resin level is high). Solutions are: avoid fully enclosed structures, periodic release holes in the vertical direction, or vertical release slots.