@ Class 5 – 3D Scanning and Printing

This, supposedly, complex part of this course, I am enjoying a lot! “3D modeling is not my domain”, was something I always had thought of and refrained from trying out. It was more of a prejudice than anything based upon experience.
No more refraining and prejudice...

Following depicts the current stage -
3D Modeling using Blender

First 3D Model Tool: Blender 2.69 Notes: 1) Wine glass seems to be a widely available example, in tutorials. This being my first attempt, I decided to fall in-line. 2) The produced file in Blender, using Extraction and Scaling tools, eventually turned out to be a Non-printable 3D model. The Units for the design were kept to be “none” and there was no wall thickness applied. 3) However, this attempt proved itself to be very important. My reluctance (fear?) to use Blender is completely gone and I will soon prodcue a 3D printable design. 4) For this to go ahead with, Blender 2.69 has a 3D Printing tool named as 3D printing tool, which is available as File -> User Preferences -> Addons -> Mesh:3D Printing Toolbox

Printable 3D Model

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Tools: Blender 2.69, netfabb basic 5.1.0 Notes: 1) Realising that the first attempt (while it was very interesting) did not produce a printable model, I moved on to learning how to produce a 3D model that can be printed. Also, I decided to go with a simpler object – a Box. 2) First taks was to start talking in “Units”. The wine glass example above did not care about any dimensions, which fine in case one wants to produce images, animation etc – not the real objects. In Blender one needs to turn on the Units explicitely. In that setting the scale to 0.001 turns the metric system into 'mm'. 3) At this point in time, I deleted the default cube and added another object – again a cube. Resiized it to 2cm x 2cm x 2cm. <more write-up about blender and netFabb handling to be added here> At the end of process in blender and netFabb, as a result - 1) The Hollow box is 2cm x 2cm x 2cm. The wall thickness is approximately 2.0038mm. 2) I checked for "select non-manifold" in blender and also repaired using Netfabb basic. Acc/to Blender and Netfabb Basic, the model is water-tight. (In general I am designing the model in Blender till "non-manifold" check and then using netfabb to repair the stl. The same stl is being treated as 3D printable.) 3) An escape hole exists on the bottom side. <write-up remains to be added here> The hollow box is realised now! - as a result of the design above, has been shown in this diagram. Let me first thank Ted Hung of Taipei Fablab, Astrid and Alex of Asmsterdam Fablab. The suggestion by Alex and Astrid (that this box be printed in Taipei Fablab) was immediately held up by Ted – unconditionally. He printed this box for me at Taipei Fablab. The unavailability of 3D printer at my end, did not hamper this process!

3D Scanning and model modification for printing back

Trial 1 - A readymade scanned object file (skull.ply) is utilised in this trial. NetFabb and meshLab are used in order to generate print-ready 3D models.
Front View	Perspective	Top View
Tool: netFabb basic Original File: Readymade_Skull.ply Note: This is a thrird party file, produced after real scanning of a laboratory skull.
Front View	Perspective	Top View
Tool: netFabb basic Output File: < > Note: using netFabb the original ply file was edited (removal of hanging 3D surfaces and then Repairing to generate a Filled-up object).
Front View	Perspective	Top View
Tool: meshLab Output File: < > Note: 1) Poison filter was applied in Meshlab to produce smoother and less spiky 3D Model. 2) To reduce the number of polygons, Decimation too was applied through - Filters -> Remeshing, simplification and construction -> Quadratic Edge Collapse Detection.
Trial 2 – A known object (container for screw driver heads) is photogrpahed from different angles (60 snaps) and uploaded to 123D Catch. The output file is treated there onwards to generate a print-ready 3D model.
The Original object	Output using 123D Catch	Repaire Mode in netfabb
First Output from netFabb	Poison filter application in meshLab	Final Output viewed in netFabb
Tools: Digital Camera, 123d catch, netfabb, meshLab Output File: < > Notes: 1) netFabb allows to add-remove the triangle and surfaces. 2) Using this feature the model generated by 123D Catch was edited. Problems: 1) Cut tool in netFabb: A small process that I was willing to do is to cut the distorted bottom of 3D model. This distortion was introduced by Poison Filter in the meshLab. The cutting tool is available but after “executing cut” model is not getting divided into parts.
Trial 3 – A known object (container for screw driver heads) is scanned using Modela scanner and the propriatery s/w Dr. Picza. The scanning problems are visible in the last image. However, Trial 3 produced real good results than Trial 2. Ofcourse, it is a fact that better snapped photographs produce better results than the above, even in 123D Catch.
3D Scanner – Modela MDX20 using Dr. Picza	3D Scanned object as seen in netfabb basic	3D Scanned object as seen in meshlab

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