Short answer

For enhanced plantar pressure distribution and a softer feel, prioritize horizontal printing orientation and consider a 50% infill density for 3D printed midsoles.

Field: Modelling
Source: Scientific Reports (2025)
Method: Experimental analysis and comparative study
Evidence: Strong effect

The orientation of 3D printing layers and the density of internal infill significantly alter the mechanical and electrical properties of re-entrant midsoles, influencing their ability to distribute plantar pressure. This modelling research insight is drawn from a 2025 study published in Scientific Reports. Using Experimental analysis and comparative study, researchers explored how this design variable affects real-world outcomes. The key design takeaway: For enhanced plantar pressure distribution and a softer feel, prioritize horizontal printing orientation and consider a 50% infill density for 3D printed midsoles.

Study

ModellingNew This WeekStrong effect

3D Printed Re-entrant Midsoles: Print Direction and Infill Density Impact Rigidity and Pressure Distribution

Scientific Reports · 2025

Key Findings

01Vertical printing direction resulted in 1.5 times greater rigidity compared to horizontal direction.
02Rigidity varied across midsole regions, with the midfoot being the most rigid in the vertical direction and the heel in the horizontal direction.
03Electrical conductivity increased with higher infill density for both printing directions.
0450% infill density demonstrated optimal electrical and electromechanical properties.
05Horizontal printing direction provided a wider plantar pressure area and better pressure distribution.

Application

Design takeaway

For enhanced plantar pressure distribution and a softer feel, prioritize horizontal printing orientation and consider a 50% infill density for 3D printed midsoles.

How to apply

When designing 3D printed footwear components, experiment with different infill densities and print orientations to optimize for desired mechanical properties like flexibility, rigidity, and energy absorption.

Project actions

01When 3D printing prototypes, document the print orientation and infill settings meticulously.
02Consider testing different infill patterns in addition to density to explore further variations in mechanical properties.

Method & Evidence

AimTo investigate the impact of slicing direction (horizontal vs. vertical) and infill density on the structural, mechanical, and electrical properties of 3D printed re-entrant midsoles, and their effect on plantar pressure distribution.

MethodExperimental analysis and comparative study

ProcedureRe-entrant midsole structures were manufactured using 3D printing with varying slicing directions (horizontal and vertical) and infill densities (three levels). The manufactured midsoles were then subjected to analyses including morphology, compressive strength, electrical resistivity, electromechanical properties, and plantar pressure mapping across different regions (metatarsal, midfoot, heel).

ContextFootwear design, biomechanics, additive manufacturing

Variables

IV["Slicing direction (horizontal, vertical)","Infill density"]

DV["Rigidity","Compressive properties","Electrical properties (conductivity/resistivity)","Electromechanical properties","Plantar pressure distribution"]

CV["Re-entrant midsole structure geometry","3D printing material (filament type)","Printer model"]

Strengths & Limitations

Strengths

+Comprehensive analysis of multiple performance metrics.
+Investigation of practical design parameters (infill, print direction).

Limitations

The specific type of 3D printer and filament used can influence the results. The study did not explore the effect of post-processing techniques.

Reliability & validity

The study's validity is supported by systematic testing of multiple parameters and performance metrics. Reliability would depend on the consistency of the 3D printing process and measurement tools.

Think critically

How might the findings on print direction and infill density for midsoles be applied to other 3D printed products, such as protective gear or structural components?

Design Principles

"Material properties and performance in additive manufacturing are highly sensitive to print orientation and internal structure parameters."

Understanding how print parameters affect material performance is crucial for designing functional footwear components. This research provides data-driven insights for optimizing 3D printing processes to achieve desired midsole characteristics, such as shock absorption, stability, and electrical conductivity.

What This Means for Your Design

How you 3D print a shoe sole (which way the layers are laid down and how much material is inside) changes how it feels, how strong it is, and how it spreads out the pressure when you walk.

How to use in your project

1.Reference this study when discussing how your chosen manufacturing method (e.g., 3D printing) influences the material properties and performance of your design.

Add to My Project

Quick Cite

Paragraph starter

The manufacturing process, particularly the parameters of additive manufacturing, can significantly influence the performance characteristics of a design. For instance, research by Jung and Lee (2025) demonstrated that the slicing direction and infill density in 3D printed re-entrant midsoles critically affected their rigidity, electrical conductivity, and plantar pressure distribution, highlighting the need to carefully select these parameters to achieve desired functional outcomes.

Source

Scientific Reports

Characterization of 3D printed re-entrant midsole structure with various infill density and print direction

journal · 2025

View source

Questions About This Research

What does the research say about 3d printed re-entrant midsoles: print direction and infill density impact rigidity and pressure distribution?: For enhanced plantar pressure distribution and a softer feel, prioritize horizontal printing orientation and consider a 50% infill density for 3D printed midsoles. Evidence: Scientific Reports (2025).
Why does "3D Printed Re-entrant Midsoles: Print Direction and Infill Density Impact Rigidity and Pressure Distribution" matter for design?: Understanding how print parameters affect material performance is crucial for designing functional footwear components. This research provides data-driven insights for optimizing 3D printing processes to achieve desired midsole characteristics, such as shock absorption, stability, and electrical conductivity.
How can designers apply this research?: For enhanced plantar pressure distribution and a softer feel, prioritize horizontal printing orientation and consider a 50% infill density for 3D printed midsoles.
What were the main findings?: Vertical printing direction resulted in 1.5 times greater rigidity compared to horizontal direction.. Rigidity varied across midsole regions, with the midfoot being the most rigid in the vertical direction and the heel in the horizontal direction.. Electrical conductivity increased with higher infill density for both printing directions.. 50% infill density demonstrated optimal electrical and electromechanical properties.
What research method was used?: Experimental analysis and comparative study.
How strong is the evidence?: Evidence strength is rated Strong effect, based on a 2025 journal from Scientific Reports.
What should I do differently in my next project?: When designing 3D printed footwear components, experiment with different infill densities and print orientations to optimize for desired mechanical properties like flexibility, rigidity, and energy absorption.
What are the limitations?: The study focused on a specific re-entrant structure; results may vary for different geometries. Long-term durability and wear performance were not assessed.