frank howarth | Making the Moon @frankmakes | Uploaded March 2024 | Updated October 2024, 19 hours ago.
I've done a handful of projects where I've taken a geometric solid like a dodecahedron or an icosahedron and made that shape out of flat parts. Once I had those parts glued together, I would wood turn that into a sphere. I'd like to continue studying this technique. I really like the idea of adding patterns to the parts that make up the solid before it gets woodturned and then those patterns show up in the sphere. A different way of thinking about this that I have wanted to work with is to CNC mill a three-dimensional form into those shapes that make up the three-dimensional solid. So one idea I've had is to mill the terrain of the moon into the parts of the solid and when I put the solid together it's not actually the solid shape with sides but a sphere with the surface of the moon milled into it.
I needed to figure out how to map the surface of the moon onto a dodecahedron. What I needed was a height map of the moon mapped onto a dodecahedron. In Blender you can take a spherical environment image and map that onto a skybox. This is a technique used for gaming to make the surrounding environment for a three-dimensional game. I found a tutorial on how to do this. And it seemed that a spherical environment map is very similar to a map made from a sphere, i.e. a map of Earth or a map of the moon. I found a tutorial on how to map a spherical image onto a skybox. So what I wanted to try was to see if I could use this technique to map a map of the moon onto a dodecahedron? This seemed like it should work. And it did. I can transform the map of the moon into the map on the 12 pentagons of a dodecahedron. Once I had that, I could build each of the dodecahedron terrain models that I needed to cut out to build the moon.
What took a while was to figure out was how to divide up a sphere into the 12 pentagons that form a dodecahedron. Once I did this I could then take each of those curved pentagons and map the surface of the moon onto that curved surface. I set up a file in Blender where I could use a height map that I generated from the spherical image of the moon onto a curved pentagon. I could then save that model out to a separate file, then change the image in Blender and save out a second model and then a third and a fourth and get all 12. I then brought those models into the cam program and I could set up the CNC to cut each one of those pentagons with the surface of the moon at the right curvature to build the sphere from the dodecahedron. If that all makes sense.
I found a piece of poplar that I had and that seemed like it would work. I just went ahead and started to work on a project. At this point. I laid out all of the pentagons so they would fall along the piece of poplar. Each pentagon is different with a different surface carved into it. What I discovered is that instead of doing a parallel finishing pass where the bit goes back and forth, I can do a spiral finishing pass where the bit starts in the middle and spirals out towards the edge. And what this allows the bit to do is to stay in the same direction the entire time. It's doing the finishing pass. With the parallel finishing pass, it's doing a climbing cut, then a conventional cut, then a climbing cut, and then a conventional cut. I think the climbing cut leaves the clean surface and the conventional cut leaves the fuzzy bits.
The next problem after I have the pentagon's cut free from the poplar wood is that I need to cut the angle on the back side of the pentagons so they will go together to form a sphere. When I was doing this with flat pentagons, the edge is uniform in height so it doesn't matter where the stops are that hold the pentagon in place on the jig on the table saw.
The last problem I encountered was that the spring clamps I was going to use to hold all the pieces together while I glued them together would not hold on to the spherical shape that I had carved into the pieces. These were not the flat pentagons with the corners that I had been used to. This was now trying to hold on to a sphere and it just wasn't working. I ended up putting biscuits in the joints between each of the pentagons. This worked very well as I could put the pentagons together and have it be a complete form without any glue.
Avid CNC: avidcnc.com
Creating Cubemap Skybox: youtube.com/watch?v=4uGIeej4WFw
Tools used in this project can be found at
frankmakes.com
To see upcoming projects follow me on social media
Patreon patreon.com/user?u=16151185&utm_medium=clipboard_copy&utm_source=copyLink&utm_campaign=creatorshare_creator&utm_content=join_link
Instagram instagram.com/frank.howarth
Facebook facebook.com/FrankMakes
0:00 (introduction)
3:00 (tests)
5:51 (cut pentagons)
11:06 (free pentagons)
12:35 (angle pentagons)
13:35 (attach pentagons)
15:04 (conclusion)
I've done a handful of projects where I've taken a geometric solid like a dodecahedron or an icosahedron and made that shape out of flat parts. Once I had those parts glued together, I would wood turn that into a sphere. I'd like to continue studying this technique. I really like the idea of adding patterns to the parts that make up the solid before it gets woodturned and then those patterns show up in the sphere. A different way of thinking about this that I have wanted to work with is to CNC mill a three-dimensional form into those shapes that make up the three-dimensional solid. So one idea I've had is to mill the terrain of the moon into the parts of the solid and when I put the solid together it's not actually the solid shape with sides but a sphere with the surface of the moon milled into it.
I needed to figure out how to map the surface of the moon onto a dodecahedron. What I needed was a height map of the moon mapped onto a dodecahedron. In Blender you can take a spherical environment image and map that onto a skybox. This is a technique used for gaming to make the surrounding environment for a three-dimensional game. I found a tutorial on how to do this. And it seemed that a spherical environment map is very similar to a map made from a sphere, i.e. a map of Earth or a map of the moon. I found a tutorial on how to map a spherical image onto a skybox. So what I wanted to try was to see if I could use this technique to map a map of the moon onto a dodecahedron? This seemed like it should work. And it did. I can transform the map of the moon into the map on the 12 pentagons of a dodecahedron. Once I had that, I could build each of the dodecahedron terrain models that I needed to cut out to build the moon.
What took a while was to figure out was how to divide up a sphere into the 12 pentagons that form a dodecahedron. Once I did this I could then take each of those curved pentagons and map the surface of the moon onto that curved surface. I set up a file in Blender where I could use a height map that I generated from the spherical image of the moon onto a curved pentagon. I could then save that model out to a separate file, then change the image in Blender and save out a second model and then a third and a fourth and get all 12. I then brought those models into the cam program and I could set up the CNC to cut each one of those pentagons with the surface of the moon at the right curvature to build the sphere from the dodecahedron. If that all makes sense.
I found a piece of poplar that I had and that seemed like it would work. I just went ahead and started to work on a project. At this point. I laid out all of the pentagons so they would fall along the piece of poplar. Each pentagon is different with a different surface carved into it. What I discovered is that instead of doing a parallel finishing pass where the bit goes back and forth, I can do a spiral finishing pass where the bit starts in the middle and spirals out towards the edge. And what this allows the bit to do is to stay in the same direction the entire time. It's doing the finishing pass. With the parallel finishing pass, it's doing a climbing cut, then a conventional cut, then a climbing cut, and then a conventional cut. I think the climbing cut leaves the clean surface and the conventional cut leaves the fuzzy bits.
The next problem after I have the pentagon's cut free from the poplar wood is that I need to cut the angle on the back side of the pentagons so they will go together to form a sphere. When I was doing this with flat pentagons, the edge is uniform in height so it doesn't matter where the stops are that hold the pentagon in place on the jig on the table saw.
The last problem I encountered was that the spring clamps I was going to use to hold all the pieces together while I glued them together would not hold on to the spherical shape that I had carved into the pieces. These were not the flat pentagons with the corners that I had been used to. This was now trying to hold on to a sphere and it just wasn't working. I ended up putting biscuits in the joints between each of the pentagons. This worked very well as I could put the pentagons together and have it be a complete form without any glue.
Avid CNC: avidcnc.com
Creating Cubemap Skybox: youtube.com/watch?v=4uGIeej4WFw
Tools used in this project can be found at
frankmakes.com
To see upcoming projects follow me on social media
Patreon patreon.com/user?u=16151185&utm_medium=clipboard_copy&utm_source=copyLink&utm_campaign=creatorshare_creator&utm_content=join_link
Instagram instagram.com/frank.howarth
Facebook facebook.com/FrankMakes
0:00 (introduction)
3:00 (tests)
5:51 (cut pentagons)
11:06 (free pentagons)
12:35 (angle pentagons)
13:35 (attach pentagons)
15:04 (conclusion)
