Saturday 23 April 2016

PHOTOGRAMMETRY

The process of creating a aluminium metal 'skin' on the chosen object would first begin by creation of a 'mold' of the chosen object. This was to be achieved by fabrication of a template; a plywood shell of the hand. In order to mimic the ridges, contours and depressions of the human hand, computer visualisation software would be necessary for the remainder of the process. Through the use of computer programs and mobile phone apps, a 3D '0scan' of my hand was produced, using AutoDesk's 123D Catch. Using this app on the iPhone, countless of photographs of my hand were taken, which were then run through the app and visualised as a 3D model.



Scanned object in 123D Catch



Model displays some inconsistencies



Finger gap details lost in scan


Following 123D Catch's render of the hand model, this was then exported into AutoDesk's 123D Make, a computer software which explodes the 'caught' object and details how to construct it through the use of laser cutting. However, due to 'holes' and inconsistencies with the 3D model of the object and the photographs which were taken the model had to be repaired and patched up using another of AutoDesk's 123D apps.



Gaps between fingers are shown as solid fill



Solid fill between fingers distorts form of object


Using AutoDesk's Meshmixer, the inconsistencies in the 3D model of the hand were remodeled. By using various tools such as "Select and Discard" and "Plane Cut" unnecessary surfaces such as the table and the upper wrist were able to be removed. Additionally, in order to 'extrude' and make the fingers of the model more visable, the mesh between the fingers would be shrunk and reduced through the use of the "ShrinkSmooth" and the "Flatten" tool. Finally, in order to allow 123D Make to detect the object as a solid as opposed to a mesh with a void, the "Make Solid" function was implemented, producing the object as a solid 3D model.



Extra and unnecessary mesh was removed



Edges were trimmed and gaps between fingers were created



Mesh was 'pulled' and 'drawn' to create knuckles and ridges



Surfaces were smoothed out



The mesh was transformed into a solid object


After this process, the Meshmixer model was exported back into 123D Make to be made ready for construction. During this process different construction techniques were trialed:


Final model



Vertical Stacking



Horizontal Stacking



Interlocking



Radial


Finally, it was decided that the most efficient and most simple option would be to use horizontal stacked slices, as it not only was the easiest to construct but would prove to be the most structurally stable method of constructing an object. Additionally, the curved edges of the stacked slices are also an imitation of the human hand, creating a resounding and resembling form of the human hand. However, as the configuration of horizontal stacking would cause errors and unconnected pieces (shown highlighted in blue), the "thicken" tool had to be used to add thickness to the object. This would ultimately create an object with no errors and therefore could be successfully modeled.


Fixed, thickened final model


Following this procedure the object was ready to be laser cut and constructed.


Model ready for laser cut



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