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Geodesic Dome Concepts

Table of Contents 1 Geodesic Dome Concepts 1.1 2V/L2 Icosahedral Dome Concept 1.1.1 Dome Parameters 1.1.2 Dome Construction 1.1.3 Comments 1.2 3V Octahedral Dome Concept 1.2.1 Dome Parameters 1.2.2 Dome Construction 1.2.3 Comments 2 General Comments on Dome Concepts

Geodesic Dome Concepts

2V/L2 Icosahedral Dome Concept

The plans for this dome can be found here. The concept was built using toothpicks and a hot glue gun. The length of each strut was normalized to the length of one toothpick, meaning that the longest strut was a toothpick in length, the second longest was a certain percentage of that, et cetera.

Dome Parameters

From the website mentioned above, the following parameters for the dome were found:

• Vertices/connections: 26
  • 10 x 4-way
  • 6 x 5-way
  • 10 x 6-way
• Edges/struts and bending angles
  • A x 30: 0.54653 (15.86^o)
  • B x 35: 0.61803 (18.00^o)
  • Total: 65 struts (2 different kinds)
  • Strut variance of 13.1%¹
• Faces: 40 (3-sided)
  • A-A-A x 30 (55.57^o, 55.57^o, 68.86^o)
  • B-B-B x 10 (60.00^o, 60.00^o, 60.00^o)
  • 2 different kinds of faces
• Diameter: 2.000, radius: 1.000
• Height: 1.000 or 50.00% of diameter

¹The variance is the percent difference between the longest and shortest struts. The lower the value, the better.

Dome Construction

Using the provided dome calculator at the website mentioned above, the following strut lengths were obtained. It should be noted that the strut lengths were normalized such that the longest strut is a toothpick in length.

• Strut A: 0.8843 (2-3/16 in.)
• Strut B : 1.0000 (2-9/16 in.)

Comments

Some things learned from building this dome concept:

• Has a very rigid structure.
• If expanded to full scale, the various strut orientations would allow for easy location of mounting points for the LED clusters.
• When compared to the 3V octahedral dome, this dome is larger in size while using only five more struts.

A rough estimate of manufacturing time to construct this dome concept would be between 80 and 105 minutes based on the estimates listed below.

• Time to prepare struts (counting, measuring, and cutting):
  • 20-30 minutes
• Time to assemble struts into dome:
  • 60-75 minutes
• Total time required:
  • 80-105 minutes

3V Octahedral Dome Concept

The plans for this dome can be found here. The concept was built using toothpicks and a hot glue gun. The length of each strut was normalized to the length of one toothpick, meaning that the longest strut was a toothpick in length, the second longest was a certain percentage of that, et cetera.

Dome Parameters

From the website mentioned above, the following parameters for the dome were found:

• Vertices/connections: 25
  • 4 x 3-way
  • 9 x 4-way
  • 12 x 6-way
• Edges/struts and bending angles
  • A x 16: 0.45951 (13.28^o)
  • B x 20: 0.63246 (18.44^o)
  • C x 24: 0.67142 (19.62^o)
  • Total: 60 struts (3 different kinds)
  • Strut variance of 46.1%¹
• Faces: 36 (3-sided)
  • A-A-B x 12 (46.51^o, 46.51^o, 89.98^o)
  • B-C-C x 24 (56.20^o, 61.90^o, 61.90^o)
  • 2 different kinds of faces
• Diameter: 2.000, radius: 1.000
• Height: 1.000 or 50.00% of diameter

¹The variance is the percent difference between the longest and shortest struts. The lower the value, the better.

Dome Construction

Using the provided dome calculator at the website mentioned above, the following strut lengths were obtained. It should be noted that the strut lengths were normalized such that the longest strut is a toothpick in length.

• Strut A: 0.6844 (1-12/16 in.)
• Strut B : 0.9420 (2-7/16 in.)
• Strut C: 1.0000 (2-9/16 in.)

Comments

Some things learned from building this dome concept:

• Has a less rigid structure when compare to the 2V/L2 icosahedral dome.
• If expanded to full scale, the various strut orientations would allow for somewhat difficult location of mounting points for the LED clusters.
• When compared to the 3V octahedral dome, this dome appears to be far less "elegant".

A rough estimate of manufacturing time to construct this dome concept would be between 100 and 120 minutes based on the estimates listed below.

• Time to prepare struts (counting, measuring, and cutting):
  • 30-40 minutes
• Time to assemble struts into dome:
  • 70-80 minutes
• Total time required:
  • 100-120 minutes

General Comments on Dome Concepts

After completing the two dome concepts, the following was found:

• The domes are not too difficult to assemble.
• The most labor intensive part of manufacturing time was counting, measuring, and cutting the struts to their desired lengths.
• As the number of different strut lengths increases, the complexity of the dome increases as does the manufacturing time.