Your first 3D design will fail without knowing these 4 details

Designing 3D-printable models in CAD requires understanding four key principles that separate functional prints from failures. First, sharp interior edges concentrate mechanical stress and should be replaced with fillets to distribute load. Second, chamfers (not fillets) should be applied to base edges to combat elephant's foot and improve tactile feel without creating unsupported overhangs. Third, CAD dimensions are theoretical — layer squish causes holes to print smaller and pegs larger, so tolerances must be adjusted empirically. Fourth, FDM prints are anisotropic, meaning layer orientation relative to expected load direction is critical; the longest continuous plastic strands must align with primary forces, sometimes requiring multi-part assemblies.