2 May 2013

Todays result: Part 3, 4 and 5 of 6, the abdomen, hips, and but

The last week has been busy printing parts for my version of the pink panther woman model.

The patterns for part 3 and 4 appear more disorganised than the other parts. They don't have a simple geometric shape as the basis for the pattern. Part 5 has one one the best patterns I have worked with so far.

I have fixed the Y belt issue that caused undesirable ripples in part 2. The ripple effect could be interesting in the right place - but not for this print

Producing this model has been a lengthy involved process.
  1. Make an inside shell for the Pink Panther woman model
    • Hollow out the original Pink Panther woman model
    • Shrink the outer shell of the model by offsetting each triangle along its normal
    • Trim triangles against neighboring triangles
    • Repair
  2. Slice into 50mm layers
    • Slice up the inside shell into 50mm layers
    • Save each piece
    • Flip the triangles of the complete inside shell
    • Merge with original unmodified model
      Slice into 50mm layers
      Repair slices
      Save each piec
  3. Generate cellular patterns
    • Run algorithm to generate patterns 
    • Filter duplicate patterns
    • Inspect and select patterns
    • Find good pattern orientation and size
  4. Combine model slice and cellular pattern
    • Break the pattern into wall planes
    • Create an OpenSCAD script and render each wall as a stl file
    • Propagate the wall stls over the space occupied by the modle
    • Use OpenSCAD to intersect the internal model shell and pattern walls
    • Merge the resulting walls and outer model slice
    • Trim erroneous triangles
  5. Slice and print
    • Print a test piece in a surplus colour
    • Fix model if necessary
    • Print final in Natural transparent ABS
  6. Finish
All up I have worked on this solidly for two months now, not including the mass of resources I accumulated previously. I have had to tweak the process a lot to work around various limits in skills, my code, OpenSCAD, and time. OpenSCAD handles simple stl csg operations ok, but sometimes it just fails.

The internal walls in the resulting models overlap at the seams. I haven't been successful at combining the walls into single shells so the final stl is a collection intersecting shapes. Cura seams to handle this ok, but I believe that an accurate model would achieve better results than I am getting.

Each piece is printed at 20mms with a 0.2 layer height. This produces nice results but takes an average of 9 hours per print.