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Buildability optimizations

Comparing overhangs

The overhang solvers in Ovenbird outputs an Overhang Distribution which displays the weighted cumulative distribution of overhangs as a line graph. In the right-click menu of the Overhang Distribution, you can also choose to display bar graphs. This makes the comparison between different designs and printing schemes straightforward: The higher the curve, the more printable the Toolpath.

Example of comparing TPMS units. Gyroid and Diamond are better (1)

  1. Image adapted from: Y. Zhi, H. Chai, T. Teng, and M. Akbarzadeh, “Automated toolpath design of 3D concrete printing structural components,” Additive Manufacturing, p. 104662, 2025.

Overhang distribution can be baked for making diagrams

Example of comparing different printing schemes of the same geometry (original and flipped). The original scheme is better (1)

  1. Image adapted from: Y. Zhi, H. Chai, T. Teng, and M. Akbarzadeh, “Automated toolpath design of 3D concrete printing structural components,” Additive Manufacturing, p. 104662, 2025.

Overhang optimization

As suggested by mesh overhang, we can optimize the buildability of a mesh if we can effectively control the distribution of the surface's normal directions. Liu and Jacobson (2021) (1) introduced the method of "spherical shape analogy" that stylizes a mesh using a reference shape, where the vertices are deformed such that their normal directions match the reference shape. Overhang Optimization uses this iterative method to reduce the overhang of a mesh.

  1. H. T. D. Liu, A. Jocabson, “Normal-Driven Spherical Shape Analogies,” Computer Graphics Forum, vol. 40, no. 5, pp. 45–55, 2021.

Overhang optimization examples with fixed boundaries (gray in \(D_{B - B'}\)) showing deformation (\(D_{B - B'}\)) and overhang distributions before (\(H_{B}\)) and after (\(H_{B}'\)). Left: a shellular funicular column (1). Top right: a double-sided Gyroid TPMS unit. Bottom right: a topologically optimized branching support structure.

  1. M. Akbari and M. Akbarzadeh, “General translation of cellular to shellular polyhedral structures using reciprocity,” Structures, vol. 63, p. 106414, 2024.

Boolean finetuning

Toolpath Boolean operations are handy in manually improving the buildability at fragile locations. An example has been included in Toolpath Booleans.