Icosahedrons are Platonic Solids of 20 faces. We will create an Icosahedron from a dodecahedron.
Here is a dodecahedron shape to get started. If not, this tutorial shows how to create a dodecahedron from scratch.
Get the dodecahedron into the Polygon modeler.
Select GL Outline shading. This will enable us to select all 12 faces.
Select all faces by dragging with the move element tool. Drag a rectangle that contains the whole dodecahedron.
Select the Extrude Inset tool and make sure Region Extrude is unchecked.
Start Performing Extrude Insets in all faces, trying to get the inset as small as possible without making the extrude turn inside-out.
This is what we want to avoid. If you get this, it means you overdid it.
When the inset is as small as possible…
Change to vertex mode.
Then invert the selection (SHIFT+Cmd+I).
And delete the selected points. We almost have our icosahedron now.
Select all the vertices and perform a Tolerance Weld to join the very small pentagons into one point.
The icosahedron is ready.
