How to Choose the Best Cura Infill Pattern

Infill can be an excellent way to add strength, improve your design, and save filament for your prints. This guide covers the basics of selecting Cura infill patterns for a variety of prints.

What is an infill pattern?

3D printing is used to make parts from a variety of materials with more customizable structural characteristics than conventional manufacturing processes. To yield prints with greater strength, lighter weights, or better flexibility, the hollowness of prints can be set for specific purposes. By altering the structural settings of a print, the material and costs required can be reduced. Further, prints without heavy interiors also require far less time to print.

Inside 3D prints’ outer shells is the “infill,” and the infill pattern and density can be modified for different needs. This article covers the different types of infill patterns you can set in Cura and discuss how to select the right pattern for your print type.

Infill pattern types

Cura (4.5) includes 13 types of infill available for use, listed below in order of increasing strength:

• Lines: gridded lines laid along one axis per layer
• Zig-zag: laid in a continuous line unless interrupted by the model walls
• Grid: low-complexity grid with an adjustable scale
• Triangles: 2D triangular mesh
• Tri-hexagon: similar to the triangle pattern but with hexagons and triangles for added structural stability
• Cubic:  3D pattern of stacked cubes with various orientations
• Cubic subdivision: similar to the cubic pattern that prioritizes lower filament usage
• Octet (or tetrahedral): stacked pyramid prisms
• Quarter cubic: similar to the octet pattern with half of the prisms shifted along the surface of the remaining prisms
• Gyroid: 3D waves-like structure that distributes force evenly along the wave forms
• Concentric: 2D wave-like pattern along the wall structure, similar to water ripples
• Cross: 2D gridded cross pattern that utilizes negative space to allow for flexibility
• Cross 3D: similar to the cross pattern with shifting axis orientation to improve structural stability and rigidity

Models and figurines (low strength): Lines, zig-zag

“Standard” 3D prints (medium strength): Grid, triangles, tri-hexagon

Functional 3D prints (high strength): Cubic, cubic subdivision, octet, quarter cubic, gyroid

Flexible 3D prints: Concentric, cross, cross 3D

Infill for models and figurines

If you are printing models or figurines, your prints generally do not need to have high strength as they are not typically handled often or subject to stress.

Lines or zig-zag infill patterns are best for figurines and models because they print the fastest.

Both patterns are printed along a 2D grid in which only one axis is printed per layer. The only difference between these infill types is that lines generates multiple lines per layer whereas zig-zag is laid along one constant line unless the model shape disrupts it.

Models or figurines work well with simple infill patterns. Other light-use prints like prototypes or decorative pieces can work with these patterns as well.

Density: 0–15%

Infill for standard prints

For 3D prints that face low stress but are still subject to handling, a medium-strength infill pattern should be used. Infill patterns such as grid, triangles, or tri-hexagon are best because they provide structural stability without requiring very high print times. It is important to note that these patterns generally lead to increased print times of up to 25% compared to the simpler patterns listed above.

The triangle pattern is best for thinner and rectangular components that can support perpendicular-oriented loads more effectively than the grid pattern. The tri-hexagon pattern is best for standard prints that require greater structural stability overall as hexagons are the most efficient shape for load distribution that can reduce bowing and bending.

Density: 15–50%

Infill for functional prints

Functional 3D prints include shelf brackets, tool carriers, appliance fixtures or supports, and other prints that must hold up to potential high stress loads from multiple directions. The stronger cubic, cubic subdivision, quarter cubic, octet, and gyroid infill patterns are best for these applications.

These patterns can also be used at lower infill densities for non-functional prints owing to their design appeal. This gyroid vase, for instance, utilizes the infill pattern without an outer shell to create an aesthetically pleasing design with negative space.

Density: > 50%

Infill for flexible 3D prints

Flexible filaments should be used for prints with flexible infill patterns to ensure that the final print retains its ability to move without cracking. The best patterns for retaining structure and flexibility are concentric, cross, and cross 3D patterns.

Density: 0–100% depending on how flexible the final print should be

Advanced infill settings

Infill line direction

In addition to density, setting your infill line direction is crucial for getting good prints. Normally, this is set to 45° by default as both X and Y motors work together to print infill at maximum speed. For some prints, however, it can be helpful to orient the infill at a different angle to provide maximum strength or flexibility to the part, especially with diagonal walls.

Gradient vs. gradual Infill

Infill settings can be adjusted to change the infill style throughout the print to improve stability at different parts.

Gradient infill can be used to set a greater infill density toward the perimeter of your model. Generally, this can maintain strength and stiffness while using less material. To implement this in Cura, you can use this python script.

Although similar, gradual infill changes along the Z-axis, rather than X- and Y-axes. With a gradual infill setting, you can increase or reduce density near the top of the print compared to the bottom. This also saves material and time while providing strength and rigidity.

Varying infill densities

The newest Cura release includes the ability to set per-model settings, which allows users to specify design settings for complex models such as multiple infill densities and types in the same model.

This setting allows for multiple infill styles to provide specialized support styles at various points in the model. While setting varying infill styles and densities is not very beginner-friendly, it can be useful to learn how to do this if you often print complex models.