The Coke Puller – Part III

3D Mesh
On the first page of this article .. tutorial .. SBS .. whatever it is .. I said that what I was trying to do was create a 3D mesh from the figure that could then be uploaded to a 3D printing service. What kicked this off was me finding a free program that does just that. Autodesk 123D Catch lets you upload a series of photos of an object and then the sever at the other ends does it’s magic and converts those photos to a 3D mesh .. cloud computing. So. This next bit will be me attempting to do just that.

Whether I will succeed or not .. have no idea. When I say .. succeed I mean getting a mesh that will be ‘good nuff’. I might .. I might not. They say that when life presents you with lemons .. make lemon-aid.

Autodesk 123D Catch
I’m not going to even attempt to make a tutorial on using the program. The company has a nice series of tutorials on YouTube. What I am going to do is show what results I obtained from this experiment.

First, I took a series of 48 photos. I to 16 in a circle around the mid-line of the figure .. then another 16 from above and another 16 from below. Why 16? I have the figure on one of those folding wooden tables – a TV dinner table. One photo from a corner then another half-way between the corner and a side .. or 22.5° intervals. I may have to increase that – if I took 5 photos per side plus the corners that would give me 24 photos. A circular series .. high, middle and low would mean a total of 72 photos.

The program on your desktop uploads the photos to a remote sever. That’s where the processing takes place and then sends you back the file. Cloud Computing. The photo to the left is the result after the file is returned. You can then modify the mesh (delete junk out – like – I have the figure on a couple of wires stuck in a wooden plaque.) .. save .. and export. That is thing I’m interested in .. the export of a 3D mesh.

Notice that the figure is laying on his side. That’s because I set my camera up on the tripod so the long axis of the photos would be vertical.

Exported 3D Mesh
I exported the 3D mesh as an .obj file and imported it into MeshLab where I exported it as a .stl file which I then imported into Sketchup. On the left is the 3D mesh as imported into Meshlab and on the right is the .stl file in Sketchup.

One of the first things to note is what looks like .. donno .. goo .. between his arm and leg. This is an artifact of the 3D process.

I believe that it is an artifact from having too few photos. The point where the ‘goo’ appears there was too wide a separation between photos.

A view from the back shows material left all the way from his wrist up to his armpit. Again .. I think that this could be an artifact of the number and angle that the photos were taken.

Again, the MeshLab screen-grab of the .obj file is on the left and the right has the .stl file as shown in Sketchup.

Now, let’s scroll in for a close-up of the head. On the left is the .stl file as rendered in Kerkythea in bronze. On the right the .stl file as displayed in Sketchup.

Bummer. This mesh is the default or ‘Standard’ resolution mesh as created by the program. The question is .. is this a limitation of the program, a result of lack of focus of the photo(s) or something else? This is certainly too crude for what I need it for. It’s close though. Remember .. my original need was to reproduce this as an O scale figure. It isn’t good enough for that .. yet. It approaches that level but not quite.

Maximum Quality Mesh
You can change the Mesh Quality. I changed to “Maxium“. It says .. “Very high density mesh, suitable for manipulating in external applications.

Ok. Well .. the mesh is more finely sub-divided but the quality of the figure hasn’t changed to any great extent. On the left is the ‘Standard’ mesh and on the right the ‘Maximum’ mesh. From this I think the problem isn’t the mesh .. as such .. but the data fed into the Cloud.

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