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Goldberg Polyhedron Mold Enginebeta

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Dome Parameters

4
162 total faces
36"
4"
90°
Hemisphere (max floor area)

Display

0%
Tight (real fit)

Export STL

STL files are exported in millimeters, oriented for direct 3D printing.

Click a face to highlight its type · Drag to orbit · Scroll to zoom

Dome Stats

Total bricks91
Full bricks71
Cut (edge) bricks20
Unique shapes7
Outer diameter36"
Inner diameter28"
Approx height18.0"
Inner cooking floor4.3 ft²
FrequencyGP(4,0)
Full sphere faces162
Pentagons (full)12
Hexagons (full)150

Brick Types

Full bricks
Pentagon5 sides
Count in dome: 6
Max span: 4.9"
Edges: 2.9, 2.9, 2.9, 2.9, 2.9"
Hexagon A6 sides
Count in dome: 30
Max span: 6.2"
Edges: 2.8, 3.2, 3.2, 3.2, 2.8, 2.9"
Hexagon B6 sides
Count in dome: 10
Max span: 6.4"
Edges: 3.2, 3.2, 3.2, 3.2, 3.2, 3.2"
Hexagon C6 sides
Count in dome: 25
Max span: 6.6"
Edges: 3.2, 3.2, 3.3, 3.3, 3.2, 3.2"
Cut bricks (dome rim)
Cut A5 sides
Count in dome: 10
From hexagon, trimmed at cut plane
Max span: 6.2"
Edges: 3.2, 1.7, 5.6, 1.5, 3.2"
Cut B5 sides
Count in dome: 5
From hexagon, trimmed at cut plane
Max span: 6.3"
Edges: 3.3, 3.3, 1.7, 5.7, 1.7"
Cut C5 sides
Count in dome: 5
From hexagon, trimmed at cut plane
Max span: 6.2"
Edges: 1.5, 3.2, 3.2, 1.5, 5.7"

About the Goldberg Polyhedron Mold Engine

The Geometry

A GP(4,0) Goldberg polyhedron is the dual of a Class I geodesic sphere at frequency 4. It has exactly 12 pentagonal faces and 150 hexagonal faces. Bricks crossing the cut plane are trimmed into partial shapes — these are listed as "Cut bricks" with their own molds.

Brick Construction

Each brick is a curved panel 4" thick, with the outer surface following the dome's spherical curvature. Recommended composite: firebrick aggregate, perlite insulation layer, and CSA cement for rapid curing.

STL Molds (mm)

Molds are thin-walled shells matching each brick's perimeter — open at both ends, tapered to flare outward going up. The cavity floor is flattened to a single plane and an optional flange wraps the base, so the whole bottom rim sits flush on the print bed. Print with no supports, cast on melamine. All STLs are in millimeters.