lordi/solidpython

A python frontend for solid modelling

PyOpenSCAD/ SolidPython

PyOpenSCAD is a generalization of Phillip Tiefenbacher's openscad module, found at http://www.thingiverse.com/thing:1481. It generates valid OpenSCAD code from Python code with minimal overhead. Here's a simple example:

This Python code:

from pyopenscad import *
d = difference()(
    cube(10),
    sphere(15)
)
print scad_render( d)

Generates this OpenSCAD code:

difference(){
    cube(10);
    sphere(15);
}

Steps to using PyOpenSCAD

• from pyopenscad import *

• call use( "/path/to/scadfile.scad") or include("/path/to/scadfile.scad") for any included SCAD code

• OpenSCAD uses curly-brace blocks ({}) to create its tree. PyOpenSCAD uses parentheses with comma-delimited lists.

  • OpenSCAD:

  difference(){ cube(10); sphere(15); }

  • PyOpenSCAD:

  d = difference()( cube(10), # Note the comma between each element! sphere(15) )

• Call scad_render( py_scad_obj) to generate SCAD code. This returns a string of valid OpenSCAD code.

• or: call scad_render_to_file( py_scad_obj, filepath) to store that code in a file.

• If 'filepath' is open in the OpenSCAD IDE and Design => 'Automatic Reload and Compile' is checked, calling scad_render_to_file() from Python will load the object in the IDE.

• Alternately, you could call OpenSCAD's command line and render straight to STL.

Extra syntactic sugar

Basic operators

Following Elmo Mäntynen's suggestion, SCAD objects override the basic operators + (union), - (difference), and * (intersection). So

c = cylinder( r=10, h=5) + cylinder( r=2, h=30)

is the same as:

c = union()(
    cylinder( r=10, h=5),
    cylinder( r=2, h=30)
)

Likewise:

c = cylinder( r=10, h=5)
c -= cylinder( r=2, h=30)

is the same as:

c = difference()(
    cylinder( r=10, h=5),
    cylinder( r=2, h=30)
)

SP_utils

I've been adding utilities to sp_utils.py. Currently these include:

Basic color library

I took this from someone on Thingiverse and I'm ashamed that I can't find the original source. I owe someone some attribution.

Directions: (up, down, left, right, forward, back) for arranging things:

up(10)(
    cylinder()
)

seems a lot clearer to me than:

transform( [0,0,10])(
    cylinder()
)

Again, I took this from someone's SCAD work and have lost track of the original author. My apologies.

Arcs

I've found this useful for fillets and rounds. arc( rad=10, 90, 210) draws an arc of radius 10 counterclockwise from 90 to 210 degrees. arc( rad=10, 0, 90, invert=True ) draws the portion of a 10x10 square NOT in a 90 degree circle of radius 10. This is the shape you need to add to make fillets or remove to make rounds.

Bill Of Materials

Put @part() before any method that defines a part, then call bill_of_materials() after the program is run, and all parts will be counted, priced and reported. Check it out.

Advantages

Because you're using Python, a lot of things are easy that would be hard or impossible in pure OpenSCAD. Among these are:

• recursion
• built-in dictionary types
• mutable, slice-able list and string types
• external libraries (images! 3D geometry! web-scraping! ...)

Enjoy, and please send any questions or bug reports to me at [email protected]. Cheers! Evan