I’m sure there are 20 different ways to create a 20 sided dice
but this is my way.
Open Sketchup and If you still have your starter person, get rid of them.
Step 1: Goldent Rectangle
Select the rectangle tool and create a Golden Rectangle.
To do this I like to click on the origin and drag the cursor out until you get to the Golden Rectangle. (This will be indicated by four solid lines in a rectangle and a dotted diagonal line from the origin to the extending corner.) Click to create rectangle.
*Note - at this point it does not matter what size you need to make your dice because I will show you how to fix this in the last step.
Step 2: Golden Rectangle Component
Once the rectangle is created double click on it to select everything. Once everything is selected right click on the rectangle and select – Make Component. In the Create Component dialog you can name it whatever you like as this is just temporary, but make sure that Replace Selection with Component is checked. Then click create.
Step 3: Some Locking Points
Select the Line tool and on the rectangle component (not inside the component) create an X. This will be used for lining everything up.
Step 4: A Little Roatation
While the Rectangle component is highlighted look at your Rectangle component from the narrow side. Select the Rotation tool and hold the shift key down to lock the tool onto the Red orientation.
Step 5: Now There Are Two
Click on the center point of narrow side. Once selected click the Ctrl key on the keyboard and rotate the rectangle 90 degrees. By clicking the Ctrl key you create a second component that is 90 degrees from the original component.
Step 6: Rotating...
Rotate your view again so you are looking at the rectangle in the original direction. Hold the Shift Key down to lock the Rotation tool into the Green orientation. Lock the tool into the center of the original rectangle. (This is easier now because of the X we created on the original Component.) Rotate the rectangle 90 degrees.
Step 7: And Now There Are Three!
Once again hold the Shift key down to lock on the Green orientation and lock into the Center. Click the Ctrl key to create a new rectangle and rotate the new rectangle 90 degrees.
Step 8: I Really Hope You Look Like This Now.
Hold Shift down to lock the Rotation tool into the Blue orientation. Click on the center of the X and rotate the last rectangle 90 degrees. You should end up with a shape that looks like this.
Step 9: A Single Triangle.
From this point on it is point and click. Select the Line tool. On every short end create a triangle to the long end of the opposing rectangle.
From the starting point draw a line to point 2 and then to point 3 and then back to the starting point to create a triangle.
Step 10: Proper Orentiation
Once you have completed this, your Icosahedron will be complete. When I completed mine a few of the sides were reversed so I right clicked on the reversed side and clicked on Reverse Faces to correct their orientation.
Step 11: The Final Component
Once all the sides are orientated correctly, double click on a side to select everything. Right click and select Create Component. This time I took the time to name the component as Icosahedron and made sure Replace selection with Component was checked. Then click Create.
Step 12: Starting Cleanup
Once the component was created I right clicked on it and selected Hide. With the new component hidden I could then delete the 3 Golden rectangles I started with.
After those were deleted I went to the file menu and clicked Edit>Unhide>All. This brought back my dice.
Step 13: Finishing the Cleanup
I then double clicked to edit the Component. Then right click on a side and click Hide.
Delete all the internal structures, so all you have left is the External structure.
After this is done once again on the file menu click Edit>Unhide>All. This will bring back your missing pane and your Icosahedron is complete!
Step 14: Well Almost Complete - Sizing It Up
Now that you’re dice is complete, you may want it to be a specific size. Make sure nothing in your component is selected, and if you’re in component edit click outside of the component to close the edit out. With nothing highlighted or selected click on the Tape Measure Tool. Select the point you want to be your measurement. (In my example I want a side to be half an inch). Click on one point of the side and then click on the second point of the side. In my case my single side is 18 feet 7 and 7/16 inches. After clicking both sides the measurement will show in the bottom right corner. Without touching any other tools type in .5 on your keyboard and hit Enter. This will bring up a dialog. When you click Yes, your Dice will be half an inch per side.