OpenVCAD: Open-Source Software Simplifies Design Processes for Multi-Material 3D Printing

A research team at the University of Colorado Boulder has developed a new open-source tool designed to simplify the creation of complex multi-material objects in 3D printing. The system, called OpenVCAD, was created by Charles Wade, a PhD student in the Department of Computer Science, within the Matter Assembly Computation Lab led by Assistant Professor Robert MacCurdy. The goal is to provide engineers with a flexible, programmable environment that allows for the precise definition not only of shapes but also of material distributions.

Traditional CAD systems often reach their limits when designing parts composed of multiple materials, as they typically represent only surface geometries and interpret the interior of an object as a single homogeneous material. OpenVCAD, on the other hand, uses a functional, code-based approach that enables spatially variable assignment of material properties. This allows for the creation of so-called gradient structures, where two materials can seamlessly transition into one another—an approach that is gaining increasing relevance in fields such as medical engineering, robotics, and materials science.

“There’s certainly a history of multi-material design study and practice that existed well before OpenVCAD,” said MacCurdy, who is also affiliated with computer science and the Department of Electrical, Computer and Energy Engineering. “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. With OpenVCAD, we’re doing all of that work once—and doing it really well—so that people have built-in infrastructure to represent these spatially varying multimaterial designs.”

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

In tests with various multi-material 3D printers—including systems capable of processing up to five materials simultaneously—OpenVCAD demonstrated the ability to achieve precise transitions between materials and define localized mechanical properties within an object. This opens new possibilities for printing medical models, flexible robotic components, and lightweight, shock-absorbing lattice structures.

“We’re able to rely on OpenVCAD’s core capabilities to represent multi-material objects in a bunch of different domains,” said MacCurdy. “But there is a lot more coming in certain areas that we are excited about and we’re really hoping this approach to multi-material design takes off.”

“We want this to be widely available to people,” Wade said. “We have a growing base of external researchers from other institutions who are using this tool and we hope to enable that community to do their best work.”