Slotted soap dish with drain channel
Bar soap turns to mush in a flat dish, while a slotted tray drains water and lets air reach the underside. The dish is 110 x 80 mm with six 3 mm ribs 5 mm tall running lengthwise, a 2 mm floor sloped 3 degrees toward a 10 mm drain spout, and 8 mm walls with 2 mm fillets. Printing it flat in PETG or ASA avoids the water absorption issues of PLA and the ribs need no supports.
SpeakCAD makes the dish to your soap size and sink corner, and you can ask for a wall-hung version or a removable rib insert in the chat without redrawing. Preview is free in the browser; the STL only costs credits at download.
Design a soap dish 110 x 80 x 15 mm with 2 mm walls, six 3 mm wide ribs 5 mm tall along the length, a 2 mm floor sloped 3 degrees toward a 10 mm wide drain spout on one short end, and 2 mm fillets on all edges.