The Two Labyrinths
ADMS geometry has a property that creates two completely separate, continuous internal channels. These are called labyrinths. Understanding them explains why ADMS works so well for heat exchangers, CFD simulation, and controlled cavity design.
What the labyrinths are
The ADMS minimal surface divides the interior of your envelope into two interlocking volumes. These two volumes are:
- Continuous throughout the entire part, with no dead ends or enclosed pockets.
- Completely separate from each other. The two channels never connect or cross.
- Geometrically complementary: together they fill the entire void space inside the envelope.
Think of a gyroid or other TPMS structure: all TPMS surfaces do the same thing. ADMS extends this principle by making the surface adaptive (changing density and thickness across the volume) while maintaining the two-labyrinth property everywhere.
Why this matters for printing
The open labyrinth structure is one of ADMS's key advantages for additive manufacturing. Because neither channel is a closed pocket, powder and resin can always evacuate after printing. There is no trapped material, no pressure buildup, and no need for drainage holes.
This makes ADMS compatible with all major additive manufacturing processes: LPBF, SLM, SLS, MJF, FFF, and resin-based methods. No special powder evacuation strategy is required.
Front and back labyrinths
The two channels are referred to as the front labyrinth and the back labyrinth (also called anterior and posterior in some contexts).
In most structural applications the distinction between front and back is not significant. But in heat exchanger and fluid flow applications, the two labyrinths become the two separate fluid channels:
- One labyrinth carries the hot fluid.
- The other carries the cold fluid.
- The ADMS wall between them acts as the heat transfer surface.
Cavities can be applied independently to either the front or back labyrinth, giving you precise control over where voids appear within each channel independently.
How to work with the labyrinths in practice
|
Task |
How to do it |
|
Visualise which is front/back |
Use the Labyrinth Color Scheme colorization in the compute dialog to colour-code each labyrinth differently on the solid surface output. |
|
Add a cavity to one labyrinth only |
Use the CavityFront or CavityBack input (nTop) or select Front/Back Labyrinth in the cavity dialog (Fusion, Rhino). |
|
Close the opening at a face |
Use a Boundary modifier with Apply on Front or Apply on Back enabled. |
|
Export for CFD |
Select Labyrinths as the output type. Each labyrinth is output as a separate solid mesh body. |
|
Inspect channel connectivity |
Export the labyrinths and visually verify in your CAD tool that each channel runs continuously through the part. |
Labyrinths and self-supporting geometry
Because neither labyrinth is enclosed, ADMS geometry never creates fully sealed internal voids. This is a key requirement for self-supporting AM geometry. Sealed internal voids trap gas during metal printing, which can cause porosity or part failure.
The two-labyrinth structure ensures that every internal region of the ADMS is accessible from the outside, keeping the geometry AM-compatible by default