To explore the production techniques which could be used to archive the sculpture and represent its features on a smaller scale, the process below explains how the 3D model generated from photographs could be used to duplicate elements of the sculpture by 3D printing the model.
Autodesk Netfabb was the next stage of processing the 3D model generated in Autodesk Recap. Two file versions were worked with at this stage. The format the 3D Printer requires is .stl (Standard Tessellation Language), this turns the model into coding which acts as instructions for the 3D Printer. In Autodesk Recap the file options are .obj or .rcm, these have to be converted to .stl files. Autodesk Netfabb allows you to import an .obj file and export it as a .stl file ready for 3D Printing. The imported model was too large for the 3D printer and Netfabb allowed this to be scaled down to a suitable size for 3D Printing.
I set the model at a size which would fit on the 200mm x 200mm x 200mm 3D Printing bed on the Ultimaker 2+ 3D Printer. To allow a tolerance on the printing bed the maximum advisable size to work with is 190mm x 190mm x 190mm, this is to prevent the 3D Printer having to print too close to its edge. During this stage I set the model square on the printing plane to determine how much support would be needed underneath the model and to ensure the height did not exceed 190mm with a base. Within Netfabb you can also ‘clean up’ the model, which is where gaps / holes in the 3D mesh are infilled to prevent the model collapsing during printing.
Once the .STL file was ready after export it could be set up in the Ultimaker Cura program. Settings could be chosen to automatically calculate a base size for the model. The turquoise colour on the screen above is the base which was generated. As you can see this was relatively deep, this was needed to support the lowest point of the model.
Ultimaker Cura calculates a printing time and length of material required to create the model. The model can be checked in the software prior to printing to determine if any gaps / holes will appear in the physical model. This is a similar process carried out in Netfabb.
The x axis plane could be moved up and down to view the density of the physical model at different levels.
The changes in colour represent where the density changes within the model. This was particularly important to assess the base to ensure that it was not too dense, but still dense enough to support the model during printing.
In Ultimaker Cura I was able to control the density of the base the model was printed on, due to this being a less important part of the final output, a much lower density was selected. This also helped reduce the 3D printing time and the length of material required.
Summary
This process was a learning curve, working with new software and technology to recreate something which was made using more manual methods will open conversations for how sculptures can be archived at a smaller scale. It will be interesting to see how the model turns out, whether it is an accurate representation and whether it can be used as part of a more mobile exhibition. Even though casts are unlikely to be made from this 3D printed model, the physical artifact can still act as a tool for discussion. The main benefit of this process will be to have a physical replica of part of the sculpture which is away from the original setting and can be transported from place to place.
In the coming weeks this process I have been through can be refined to generate more complete outputs which could potentially be used for casting multiple replicas in various alternative materials.
Michael Conner
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