Infill

Definition

Infill refers to the internal structure of a 3D printed model — rather than being solid, the interior is filled with a specific pattern of grid, honeycomb, or straight lines. Infill density is expressed as a percentage — 0% means completely hollow, while 100% is fully solid.

Simple Analogy

Think of bones — bird bones have a honeycomb interior, making them both light and strong. Infill works on the same principle: while keeping the outer shell and surface intact, the interior uses minimal material to achieve the required strength. It’s like the steel framework of a building, supporting the entire structure with the least amount of steel.

Why It Matters

Infill density and pattern selection directly affect three key factors:

• Strength: Higher infill density produces stronger models. 0% crushes easily, while 100% is nearly indestructible with a hammer.
• Weight and material consumption: A 20% infill model uses only about 25-30% of the material (compared to solid), while 50% infill uses roughly 50-60%.
• Print time: Higher infill density means longer print times. A 100% infill print takes about 3-4 times longer than a 20% infill print.

Practical Advice

Use Case	Recommended Infill	Recommended Pattern
Display figurines, decorative items	5-10%	Grid
Everyday tools, containers	15-25%	Honeycomb or Tri-Hex
Load-bearing parts, brackets	30-50%	Gyroid
Mechanical tools, fixtures	60-80%	Gyroid
Stamping molds, extreme loads	100%	Solid

Gyroid has become the most popular infill pattern in recent years — it distributes force evenly in all directions, uses a moderate amount of material, and doesn’t require retraction during printing, making it highly efficient. Beginners who master 15-25% Gyroid infill can cover 80% of their daily printing needs.