Software unlocks 3D printing gradients for advanced engineering

October 14, 2025
Imma Perfetto

Imma Perfetto

Cosmos science journalist
A cube-shaped lattice structure made out of green and blue materials which seamlessly transition from one colour to the other
A graded lattice with soft and rigid parts. OpenVCAD can apply specific mechanical properties to certain parts of lattice structures, which are often used for impact-absorbing capabilities, to achieve more complicated designs. Credit: University of Colorado Boulder

Engineers will have an easier time 3D printing objects out of multiple different materials with the release of an open-source tool, OpenVCAD, that can convert complex gradient designs into printer ready code for advanced engineering applications.

Designing and 3D printing gradients, where 2 materials gradually blend from one to another, is extremely difficult.

Conventional computer-aided design (CAD) software tends to assume that the same material exists within the boundaries of the different areas within a 3D design and struggle to produce objects with truly continuous gradients.

Cross section of a 3d printed model of a human brain with different regions made with differently coloured materials
A scan‑to‑print medical model, which surgeons could use to plan surgeries, printed using OpenVCAD. Credit: University of Colorado Boulder

“Unlike traditional CAD software, where you’re forced to sketch everything out for each change and you cannot represent graded materials, our tool allows users to change one small variable and watch the whole design update in an easy way,” says Robert MacCurdy, who led the project in the Matter Assembly Computation Lab at the University of Colorado Boulder, USA.

“This is the first multi-material, code-based design tool that is widely available. It allows for good complexity when printing objects, it’s accessible and it’s intuitive to write and design.”

Materials with continuous gradients, called ‘functionally graded materials’, can enhance the mechanical performance of materials, optimise weight distribution and eliminate sharp interfaces between materials where stress could concentrate in an object.

A small teapot made of yellow, orange and purple materials which gradually transition like a sunset
A 3D printed gradient teapot made from 3 different materials. Credit: University of Colorado Boulder

“There’s certainly a history of multi-material design study and practice that existed well before OpenVCAD,” says MacCurdy.

“But we believe the overhead of writing specific code for specific projects every single time prevents engineers from doing as much design as they could.”

The researchers anticipate using OpenVCAD to more efficiently design print graded electronics, sensors and radio-frequency components for devices. They also suggest that the method could combine fundamentally different materials, such as flexible elastomers and rigid polymers, to enable new designs in soft robotics.

The software is presented in a paper published in the journal Additive Manufacturing.

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