After reviewing nearly every three‑way fitting model in the community and printing several such fittings based on existing designs, we found that none fully met our expectations during actual use.

Building on this insight, we designed the following model with the goal of addressing two key challenges:

1. When certain three‑way fittings are printed in a vertical orientation, the printing process becomes significantly more challenging. Unfavorable print orientations often lead to parts that are prone to detachment and difficult to fully form.

2. Almost all existing three‑way fittings feature circular holes. During vertical printing, layer lines can severely impact internal flow smoothness, making it difficult to achieve a completely seamless interior. When printed on their side, the upper sections tend to warp due to filament deposition, and if the unsupported walls aren’t properly adhered, they’re highly susceptible to sagging—leading to blockages within the pipe.

To address these issues, our model adopts the following design approach:

1. Print horizontally to reduce print time, improve build quality, and enhance overall model strength.

2. Design non‑circular holes tailored to the print orientation, carefully managing filament deposition to keep overhang distortions within acceptable limits while maintaining optimal internal surface smoothness.