3V 5/8 sphere geodesic dome
Class I icosahedral breakdown, cut snapped to the nearest vertex ring (achieved portion 58.8%). 165 struts in 3 lengths, 61 hubs, 105 panels. Strut length = chord factor × sphere radius.
Open this geometry in the studio
Struts
| Strut | Qty | Chord factor | 12 ft dome | 16 ft dome | 20 ft dome | 24 ft dome | 30 ft dome | 40 ft dome |
|---|---|---|---|---|---|---|---|---|
| A | 30 | 0.34862 | 2' 1 1/8" | 2' 9 7/16" | 3' 5 13/16" | 4' 2 3/16" | 5' 2 3/4" | 6' 11 11/16" |
| B | 55 | 0.40355 | 2' 5 1/16" | 3' 2 3/4" | 4' 0 7/16" | 4' 10 1/8" | 6' 0 5/8" | 8' 0 7/8" |
| C | 80 | 0.41241 | 2' 5 11/16" | 3' 3 9/16" | 4' 1 1/2" | 4' 11 3/8" | 6' 2 1/4" | 8' 3" |
| Total | 165 | 394 lin ft | 525 lin ft | 656 lin ft | 788 lin ft | 985 lin ft | 1,313 lin ft |
Cut lengths are hub-centre to hub-centre; subtract your hub's offset at each end.
Hubs
| Valence | Qty |
|---|---|
| 6-way | 40 |
| 5-way | 6 |
| 4-way (base) | 15 |
| Total | 61 |
Panels
| Signature | Qty | Area (unit R) |
|---|---|---|
| AAB | 30 | 0.0574 |
| BCC | 75 | 0.0726 |
| Total | 105 | 7.164 |
Proportions (per foot of radius)
- Height 1.177 × R · floor diameter 1.968 × R
- Surface 7.164 × R² · floor 3.043 × R²
- Base ring is not flat: hubs differ by 0.0160 × R — plan a stepped base plate or trim the base struts.
Computed by DomeSketch from the icosahedral geometry; the 2V/3V/4V values match the published tables and the test suite asserts it.