- A Hacker News thread was shared arguing that subdivision surfaces (common in CGI) cannot exactly represent perfect circles, cylinders, or tori, whereas trimmed NURBS can; this is framed as a critical limitation for mechanical CAD where true roundness matters for bearings, wheels, and machined features.

- The same thread prompted discussion of rational quadratic parametrizations that do yield exact circular arcs, e.g. [x,y] = [((1-t²)/(1+t²)), (2t/(1+t²))], showing that mathematically perfect circles are possible with rational polynomials.

- Counter-argument advanced that real-world precision is determined by the manufacturing process (boring, turning, grinding, etc.) and its tolerances, not by the ideal mathematical surface; process specifications are metadata separate from the geometry.

- Emphasis on non-destructive, parametric workflows: geometry should regenerate automatically when upstream parameters change, avoiding the need to redo downstream work or be locked into early decisions.

- Blender’s emerging “nodes everywhere” paradigm praised as a flexible computation graph where geometry primitives, operators, and generic numeric operations coexist and update in real time, contrasting with the perceived rigidity of OpenSCAD’s programmatic approach.

- Observation that many 3-D-printed parts—even from high-end companies—exhibit faceted surfaces because slicers and CAD tools fail to set adequate tessellation resolution, leading to noisy bearings and premature wear.

- Link shared to an open-source Python CAD framework, fscad (https://github.com/JesusFreke/fscad), as an example of programmatic solid modeling that attempts to bridge these gaps.