How can you prevent Elephant Foot when 3D printing?

Preventing Elephant Foot, a common issue that occurs when the lower layers of a 3D printed object are squished and spread out due to excessive heat or pressure, can be effectively addressed by adding fillets to the bottom parts of an object. By incorporating fillets, you create a more gradual transition between the vertical sides and the base of the print, which helps to reduce the contact area with the build plate. This design adjustment makes the object less prone to deformation caused by heat for those initial layers, leading to a cleaner bottom edge.

Considering the context of the other choices, increasing print speed significantly might improve layer cooling but could lead to issues with layer adhesion and print quality overall. Using larger filament spool sizes does not directly impact the thermal properties or the layer adhesion issues that cause Elephant Foot. Lowering the print temperature might help reduce some issues related to thermal expansion but could also lead to under-extrusion and poor layer adhesion, resulting in an inferior print overall. Therefore, adding fillets stands out as the most effective method for preventing this specific printing defect.