A new open-source software tool is transforming the way engineers design and print complex 3D objects. Developed at the University of Colorado Boulder, the program—called OpenVCAD—enables users to easily create 3D-printed objects made from multiple materials, blending engineering precision with the flexibility of coding.
Created by Charles Wade, a Ph.D. student in computer science, OpenVCAD is part of the Matter Assembly Computation Lab led by Assistant Professor Robert MacCurdy in the Paul M. Rady Department of Mechanical Engineering. Their recent paper, published in *Additive Manufacturing*, explains how this tool helps engineers design intricate, multi-material objects more efficiently than ever before.
“Before OpenVCAD, engineers often had to write custom code for every single project,” said MacCurdy. “That made the design process slow and repetitive. OpenVCAD solves this by providing a shared, ready-to-use framework for complex designs.”
Traditional 3D design software, or CAD programs, usually focus on an object’s outer surface, assuming that the material inside is uniform. However, many real-world objects—like shoes, prosthetics, or soft robots—require smooth transitions between hard and soft materials, or areas with varying flexibility and strength. This kind of design, known as gradient design, has been notoriously difficult to achieve with existing tools.
OpenVCAD changes the game. Instead of manually redrawing or reprogramming each version of a design, users can adjust functions in the code to instantly modify how materials are distributed within an object. For example, an engineer could design a shoe sole that gradually shifts from firm rubber at the bottom to soft foam near the top—all within a single digital model.
“This is the first widely available, code-based tool for multi-material 3D design,” said Wade. “It’s powerful, flexible, and easy to use. You can change a single parameter and instantly see how the entire design updates—something that traditional CAD systems can’t do.”
The research team tested OpenVCAD with several types of 3D printers, including one in MacCurdy’s lab that can print objects using up to five materials simultaneously. Thanks to its versatility, the software can be applied across many fields—from healthcare to robotics to aerospace.
Surgeons, for instance, can use OpenVCAD to design lifelike medical models for surgical training. Robotics engineers can build soft machines with controlled flexibility. Mechanical designers can create structures that absorb impact more efficiently by fine-tuning material gradients.
Because OpenVCAD is open-source and implemented in Python, anyone can download and start designing with just one line of code—completely free.
“We’ve already seen researchers from other institutions adopting it,” Wade noted. “Our goal is to empower the engineering community to create more advanced designs without the usual software limitations.”
MacCurdy added, “This approach to multi-material design has the potential to transform how people think about 3D printing. We’re just scratching the surface of what’s possible.”
With OpenVCAD, the future of 3D printing looks not just layered—but blended, efficient, and open to everyone.
https://knowridge.com/2025/10/new-open-source-software-revolutionizes-3d-printing-with-multiple-materials/
