Creating Manufacturable Blueprints for Coarse-Grained Virtual Robots

Automating the step from a freely evolved virtual body to a blueprint a builder can follow.

Published: March 2026 · arXiv preprint, under review
Authors: Zihan Guo, Muhan Li, Shuzhe Zhang, Sam Kriegman
Xenobot Lab, Northwestern University
Links: arXiv PDF Workshop poster BibTeX

An evolved tripedal design, carried through the pipeline into printable files, then printed, assembled and switched on. It walks under the policy trained in simulation, transferred zero-shot with no tuning on hardware.

#Abstract

Over the past three decades, countless embodied yet virtual agents have freely evolved inside computer simulations, but vanishingly few were realized as physical robots. This is because evolution was conducted at a level of abstraction that was convenient for freeform body generation (creation, mutation, recombination) but swept away almost all of the physical details of functional body parts. The resulting designs were crude and underdetermined, requiring considerable effort and expertise to convert into a manufacturable format. Here, we automate this mapping from simplified design spaces that are readily evolvable to complete blueprints that can be directly followed by a builder. The pipeline incrementally resolves manufacturing constraints by embedding the structural and functional semantics of motors, electronics, batteries, and wiring into the abstract virtual design. In lieu of evolution, a user-defined or AI-generated “sketch” of a body plan can also be fed as input to the pipeline, providing a versatile framework for accelerating the design of novel robots.

#Method

A body that evolution is free to reshape has to be cheap to describe, so it is described as voxels and nothing else. A body a printer can build has to say where every motor sits, where the controller and battery live, and how each wire reaches them. The pipeline closes that gap in stages rather than in one step, so each stage has only one kind of constraint to satisfy.

A virtual voxel creature is split into rigid bone and soft skin, passed through motor, electronics and wire solver nodes, and emerges as an assembled physical robot — **Four stages from virtual to real.** The coarse voxel body is first separated into rigid bone and soft skin. A motor solver places each actuator along its joint axis, an electronics solver carves cavities for the controller and battery, and a wire solver routes geodesic channels through the body to reach them. What leaves the pipeline is a multi-material printing file, not a suggestion.

The generated blueprint opened directly in a 3D printing slicer — The output loads straight into a slicer with no manual CAD work in between, which is the part that used to take expertise and days.

#Results

Across 1,000 randomly sampled designs, 67% passed every solver stage, which measures how much of a freely evolved design space the pipeline can actually reach. One evolved tripedal design was taken the whole way, printed, assembled and run under its simulation-trained policy. It walked with zero-shot transfer, and that run is the clip at the top of this page.

Four panels: a hand-drawn voxel sketch, its semi-virtual form, the semi-real blueprint, and the printed robot — **Evolution is not the only input.** A body plan drawn by hand enters at A and leaves at D as an assembled robot, passing through the same stages. The pipeline is a route from any coarse design, human or machine authored, to something that can be built.

#Citation

@article{guo2026blueprints,
  title   = {Creating Manufacturable Blueprints
             for Coarse-Grained Virtual Robots},
  author  = {Guo, Zihan and Li, Muhan and Zhang, Shuzhe
             and Kriegman, Sam},
  journal = {arXiv preprint arXiv:2603.13582},
  year    = {2026}
}