deadsy · HackerTrans

vor 4 Jahrendiscuss

I wrote this (in golang) to satisfy my need to generate STLs for 3d printing.

https://github.com/deadsy/sdfx

In general I like to write code to define objects, but there are some situations where a graphical editing UI would be nice. ie- Curve and polygon design.

You can sort of imagine a hybrid approach where you could crack open a mini editor to design a curve and then use it to generate code (table of numbers) which you could then extrude/sweep/loft or whatever.

deadsy

vor 6 Jahrendiscuss

3d = stl, 2d = svg or dxf

deadsy

vor 6 Jahrendiscuss

SDF = signed distance function. A function mapping a 2d/3d coordinate onto a scalar. The scalar is the shortest distance from that point to the surface of the object. (+ve outside, -ve inside)

CSG = constructive solid geometry: Take primitive 3d shapes and do unions, differences, intersections on them to build more complex shapes.

Fairly obviously the union of 2 sdf functions is going to be the minimum of those values. That pretty simple.

Intersections and differences are not much more complex....

See: https://iquilezles.org/www/articles/distfunctions/distfuncti...

for some quick examples.

deadsy

vor 6 Jahrendiscuss

I started with OpenSCAD but: a) found the language to be clunky b) had a hard time doing chamfered unions between objects (needed for sand casting patterns).

So - I wrote my own tool/library in Go and it's essentially replaced my OpenSCAD usage.

https://github.com/deadsy/sdfx

deadsy

vor 6 Jahrendiscuss

I wrote a CAD package in Go that has a function for it.

https://github.com/deadsy/sdfx

  func InvoluteGear(
   numberTeeth int, // number of gear teeth
   gearModule float64, // pitch circle diameter / number of gear teeth
   pressureAngle float64, // gear pressure angle (radians)
   backlash float64, // backlash expressed as per-tooth distance at pitch circumference
   clearance float64, // additional root clearance
   ringWidth float64, // width of ring wall (from root circle)
   facets int, // number of facets for involute flank
  )

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