3D Printing Infill Patterns & Percentages Explained: Gyroid vs Grid vs Cubic

Infill is the internal structure printed inside the outer walls of a model. It supports the top surfaces, adds stiffness and determines a large part of the print time and filament use. Many beginners set infill high “to be safe” and end up with heavy, slow prints that are barely stronger than they would have been at a fraction of the infill.

This guide explains how infill contributes to strength, compares the most useful patterns, and gives practical percentages for decorative, everyday and functional prints.

What infill does — and what it doesn't

Infill has three jobs: it gives the top layers something to bridge across, it stops the walls from flexing inward, and it adds some internal strength. It is not the main source of strength in most prints. Bending and impact loads are carried mostly by the outer walls and the top and bottom skins, because that is where the material is furthest from the centre of the part.

That is why adding a wall usually does more for strength than adding 20% infill, and why most decorative models print perfectly at 10–15%. Our guide on walls versus infill explores this trade-off in depth.

Comparing the common patterns

Every slicer offers a long list of patterns, but a handful cover nearly every need. The key differences are whether a pattern is equally strong in all directions, whether the nozzle crosses over its own lines on the same layer (which can cause collisions and noise), and how fast it prints.

Infill pattern comparison
Pattern	Strength	Speed	Best for
Grid	Good in X/Y, weaker in Z	Fast	Quick everyday prints, flat parts
Lines / Rectilinear	Directional, lowest	Fastest	Drafts and purely decorative parts
Gyroid	Even in all directions	Medium	General use, flexible filaments, water-resistant parts
Cubic	Even in all directions	Fast–medium	Functional parts, boxes, organizers
Honeycomb	High, rigid	Slow	Stiff parts where print time is less important
Lightning	Supports top only	Very fast	Figures and decor that need no strength

Gyroid: the safe default

Gyroid is a continuous wavy surface that never crosses itself on a layer. It is equally strong in every direction, prints quietly, and its closed cells make it a good choice for parts that should resist water seeping through. If you are unsure, gyroid at 10–20% is rarely the wrong choice.

Grid and cubic

Grid prints two sets of crossing lines on each layer. It is fast and strong in the horizontal plane, but the nozzle crosses its own lines, which can cause catching at high speeds. Cubic stacks tilted cubes and gives near-uniform strength with good speed — a strong option for organizers and functional boxes.

Lightning

Lightning infill only grows where it is needed to support top surfaces, like the branches of a tree. It saves a large amount of time and plastic on figurines and decorative pieces, but adds almost no strength, so avoid it for anything that will carry a load.

How much infill do you really need?

Infill percentage is the density of the internal pattern. Strength rises with density, but print time and material rise roughly in step while the strength gain flattens out. Going from 15% to 30% infill may add a third more print time for a modest strength improvement that an extra wall would achieve more cheaply.

Suggested infill by use
Print type	Infill	Walls	Example
Decorative	5–15%	2–3	Figurines, ornaments, wall art
Everyday	15–20%	3	Planters, desk organizers, phone stands
Functional	20–40%	4–5	Hooks, brackets, tool holders
Heavy load	40–60%+	5–6	Mounts and parts under constant stress

Advanced infill settings worth knowing

Infill/wall overlap controls how firmly the infill joins the walls; 15–25% is typical. Too little and the infill pulls away, leaving gaps visible through thin walls. “Infill every N layers” lets the slicer print thicker infill layers less often, saving time without changing the outer finish.

Gradual or adaptive infill increases density only near the top surfaces, which saves material in tall models. Modifiers (also called height range or region modifiers) let you set higher infill in one area, such as around a screw hole, while keeping the rest light.

Diagnosing infill problems

Pillowing — bumpy or holey top surfaces — usually means the top layers do not have enough support. Increase the number of top layers (to about 0.8–1.0 mm of total top thickness), increase infill slightly, or slow the top surface. Infill visible through the walls (“ghosting” of the pattern) suggests walls that are too thin or an infill overlap that is too high.

Weak or crumbly infill can come from printing infill too fast for the hot end to melt enough plastic. Many slicers let you set infill speed separately; lowering it a little often fixes the problem without slowing the rest of the print.

Quick Checklist

Use gyroid at 10–20% as a dependable default
Add walls before raising infill when you need strength
Use lightning infill for figures and decor only
Keep 0.8–1.0 mm of top layers to avoid pillowing
Use modifiers to add infill only where it is needed

Frequently Asked Questions

Is 100% infill the strongest?: It is the densest, but not always the best. Solid parts take much longer, can warp more and are heavier. For most functional parts, 5–6 walls with 40% infill is nearly as strong and far quicker.
Which infill is best for planters and vases?: Gyroid, because its closed cells resist water wicking through the part. Combine it with 3–4 walls and a slightly higher temperature for good layer bonding.
Does infill affect how the outside looks?: Slightly. With very thin walls, the infill pattern can show through, and sparse infill can cause pillowing on top surfaces. More walls and top layers hide both effects.
Why does my slicer default to 15%?: Because it is a good balance for typical prints: enough to support top surfaces and stiffen walls, without wasting time and filament.

Infill is a supporting player, not the star. Choose gyroid or cubic for general use, keep the percentage modest, and put extra material into walls when a part needs strength. Your prints will be faster, lighter and — where it matters — just as strong.