3D Printing Infill Guide

Gyroid is a continuous, mathematically complex curved surface that winds throughout the part in all three dimensions. Its defining advantage is near-isotropic strength — the part is approximately equally strong regardless of which direction force is applied. This makes it ideal for parts where the load direction is unknown or multi-directional.

Gyroid also has outstanding shear resistance, meaning it handles twisting and lateral forces well. It prints at a moderate speed and uses a moderate amount of material. Because the path is continuous without sharp direction changes, it actually performs well on speed compared to honeycomb despite its visual complexity.

Use gyroid for: functional mechanical parts, brackets, structural components, parts subject to multi-directional stress, and any heavy-duty application where you are uncertain of the load direction.

Cubic infill creates a three-dimensional grid of interlocking cubes, providing good strength in all directions similar to gyroid — but with a simpler geometry that is slightly faster to slice and print. It performs especially well under compressive loads from multiple directions.

For large parts where weight reduction matters and gyroid may feel like overkill, cubic is an excellent default. It provides strong support for top surfaces with less material than honeycomb.

Use cubic for: large structural prints, parts with broad flat surfaces that need internal support, brackets and mounts, and any application where all-around strength is needed at a slightly faster print speed than gyroid.

The hexagonal honeycomb pattern is one of the most well-known infill types — and for good reason. Hexagons naturally distribute loads across multiple walls simultaneously, giving excellent resistance to lateral (side-to-side) stress with comparatively low material use. It is one of the most material-efficient strong patterns available.

The main drawback is print speed: honeycomb is one of the slower infill patterns due to the frequent direction changes in the toolpath — it is actually slower than gyroid despite gyroid's more complex visual geometry.

Use honeycomb for: parts primarily loaded from the sides, lightweight structural components, and situations where strength-to-weight ratio is the priority over print speed.

The triangular infill pattern distributes loads well in the X and Y plane and is particularly resistant to lateral forces and side impacts. Triangles are structurally stable in 2D (they cannot be deformed without changing a side length), which translates to solid in-plane rigidity.

Triangles are not as strong in the Z direction as gyroid or cubic, making them a 2D-strong but 3D-limited pattern. They print at a moderate speed.

Use triangles for: parts that face primarily lateral or side impact loads, panels, enclosures, and components where in-plane stiffness matters most.

Grid (also called rectilinear or crosshatch) is the classic default infill in many slicers. It is a simple 2D crisscross pattern that prints fast and provides decent compression resistance vertically (in the Z direction). It is not isotropic — it is significantly weaker in the diagonal direction.

Grid is a reasonable choice when the primary load is top-down compression and print speed matters. It is not the right choice for parts subjected to multi-directional or diagonal stress.

Use grid for: general-purpose parts, parts primarily under vertical compression, and situations where fast print time is more important than optimized strength distribution.

Lines (rectilinear with no crossing layer) is among the fastest infill patterns available — second only to Lightning. Each layer alternates direction (0° and 90°), and there is minimal cross-linking between layers. This makes it very weak in shear and poor at distributing loads across directions.

Lines excels at print speed and material savings but should only be used for non-structural or decorative parts. It is a poor choice for anything that will face real mechanical stress.

Use lines for: decorative prints, display models, fast prototypes where fit is being checked but strength is irrelevant, and any part that will not face meaningful loads.

Concentric infill traces the inner contour of the part inward in rings — like a topographic map. This pattern does not add significant structural strength to rigid prints, but it excels for flexible materials like TPU. The concentric pattern allows flexible filaments to compress and flex more naturally without stress concentrations from angular infill paths.

Concentric is also sometimes used for the top layer pattern (not infill) in aesthetic prints to create a clean visual surface.

Use concentric for: TPU and other flexible filaments at any density, and as a top surface pattern in aesthetic FDM prints.

Lightning infill is designed with exactly one goal: provide the minimal internal structure necessary to support the top layers, using as little material and time as possible. It generates branching tree-like paths that touch only where needed. The result is very fast prints with very low material use — and virtually zero structural contribution.

Lightning is not appropriate for any part that will face mechanical stress. It should be reserved entirely for display models, figurines, and objects that will never be loaded.

Use lightning for: statues, figurines, display props, and any purely decorative part where you want maximum print speed and minimum material use.