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SolidCode / SolidPython

A python frontend for solid modelling that compiles to OpenSCAD
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Hey! All the energy and improvements in this project are going into SolidPython V2. Check it out at Github <https://github.com/jeff-dh/SolidPython> or on its PyPI page <https://pypi.org/project/solidpython2/> before you commit to an older version.

SolidPython

.. image:: https://circleci.com/gh/SolidCode/SolidPython.svg?style=shield :target: https://circleci.com/gh/SolidCode/SolidPython .. image:: https://readthedocs.org/projects/solidpython/badge/?version=latest :target: http://solidpython.readthedocs.io/en/latest/?badge=latest :alt: Documentation Status

SolidPython: OpenSCAD for Python

SolidPython is a generalization of Phillip Tiefenbacher's openscad module, found on Thingiverse <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:

.. code:: python

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

Generates this OpenSCAD code:

.. code:: python

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

That doesn't seem like such a savings, but the following SolidPython code is a lot shorter (and I think clearer) than the SCAD code it compiles to:

.. code:: python

from solid import *
from solid.utils import *
d = cube(5) + right(5)(sphere(5)) - cylinder(r=2, h=6)

Generates this OpenSCAD code:

.. code::

difference(){
    union(){
        cube(5);
        translate( [5, 0,0]){
            sphere(5);
        }
    }
    cylinder(r=2, h=6);
}

Advantages

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

Installing SolidPython

Using SolidPython

Importing OpenSCAD code

Ex:

scadfile.scad

.. code::

module box(w,h,d){
    cube([w,h,d]);
}

your_file.py

.. code:: python

from solid import *

scadfile = import_scad('/path/to/scadfile.scad') 
b = scadfile.box(2,4,6)
scad_render_to_file(b, 'out_file.scad')

.. code:: python

from solid import *

# MCAD is OpenSCAD's most common utility library: https://github.com/openscad/MCAD
# If it's installed for OpenSCAD (on MacOS, at: ``$HOME/Documents/OpenSCAD/libraries``)
mcad = import_scad('MCAD')

# MCAD contains about 15 separate packages, each included as its own namespace
print(dir(mcad)) # => ['bearing', 'bitmap', 'boxes', etc...]
mount = mcad.motors.stepper_motor_mount(nema_standard=17)
scad_render_to_file(mount, 'motor_mount_file.scad')

Ex:

scadfile.scad

.. code::

module box(w,h,d){
    cube([w,h,d]);
}

your_file.py

.. code:: python

from solid import *

# use() puts the module `box()` into the global namespace
use('/path/to/scadfile.scad') 
b = box(2,4,6)
scad_render_to_file(b, 'out_file.scad')

Example Code

The best way to learn how SolidPython works is to look at the included example code. If you've installed SolidPython, the following line of Python will print(the location of ) the examples directory:

.. code:: python

import os, solid; print(os.path.dirname(solid.__file__) + '/examples')

Or browse the example code on Github here <https://github.com/SolidCode/SolidPython/tree/master/solid/examples>__

Adding your own code to the example file solid/examples/solidpython_template.py <https://github.com/SolidCode/SolidPython/blob/master/solid/examples/solidpython_template.py>__ will make some of the setup easier.

Extra syntactic sugar

Basic operators

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

.. code:: python

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

is the same as:

.. code:: python

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

Likewise:

.. code:: python

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

is the same as:

.. code:: python

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

First-class Negative Space (Holes)

OpenSCAD requires you to be very careful with the order in which you add or subtract objects. SolidPython's hole() function makes this process easier.

Consider making a joint where two pipes come together. In OpenSCAD you need to make two cylinders, union them, then make two smaller cylinders, union them, then subtract the smaller from the larger.

Using hole(), you can make a pipe, specify that its center should remain open, and then add two pipes together knowing that the central void area will stay empty no matter what other objects are added to that structure.

Example:

.. code:: python

outer = cylinder(r=pipe_od, h=seg_length)
inner = cylinder(r=pipe_id, h=seg_length)
pipe_a = outer - hole()(inner)

Once you've made something a hole, eventually you'll want to put something, like a bolt, into it. To do this, we need to specify that there's a given 'part' with a hole and that other parts may occupy the space in that hole. This is done with the part() function.

See solid/examples/hole_example.py <https://github.com/SolidCode/SolidPython/blob/master/solid/examples/hole_example.py>__ for the complete picture.

Animation

OpenSCAD has a special variable, $t, that can be used to animate motion. SolidPython can do this, too, using the special function scad_render_animated_file().

See solid/examples/animation_example.py <https://github.com/SolidCode/SolidPython/blob/master/solid/examples/animation_example.py>__ for more details.

solid.utils

SolidPython includes a number of useful functions in solid/utils.py <https://github.com/SolidCode/SolidPython/blob/master/solid/utils.py>__. Currently these include:

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

.. code:: python

up(10)(
    cylinder()
)

seems a lot clearer to me than:

.. code:: python

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

| 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.

.. code:: python

arc(rad=10, start_degrees=90, end_degrees=210)

draws an arc of radius 10 counterclockwise from 90 to 210 degrees.

.. code:: python

arc_inverted(rad=10, start_degrees=0, end_degrees=90)

draws the portion of a 10x10 square NOT in a 90 degree circle of radius

  1. This is the shape you need to add to make fillets or remove to make rounds.

Extrude Along Path

solid.utils.extrude_along_path() is quite powerful. It can do everything that OpenSCAD's linear_extrude() and rotate_extrude() can do, and lots, lots more. Scale to custom values throughout the extrusion. Rotate smoothly through the entire extrusion or specify particular rotations for each step. Apply arbitrary transform functions to every point in the extrusion.

See solid/examples/path_extrude_example.py <https://github.com/SolidCode/SolidPython/blob/master/solid/examples/path_extrude_example.py>__ for use.

Bill Of Materials

Put @bom_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.

The example file solid/examples/bom_scad.py <https://github.com/SolidCode/SolidPython/blob/master/solid/examples/bom_scad.py>__ illustrates this. Check it out.

solid.screw_thread

solid.screw_thread includes a method, thread() that makes internal and external screw threads.

See solid/examples/screw_thread_example.py <https://github.com/SolidCode/SolidPython/blob/master/solid/examples/screw_thread_example.py>__ for more details.

solid.splines

solid.splines contains functions to generate smooth Catmull-Rom curves through control points.

::

from solid import translate
from solid.splines import catmull_rom_polygon, bezier_polygon
from euclid3 import Point2

points = [ Point2(0,0), Point2(1,1), Point2(2,1), Point2(2,-1) ]  
shape = catmull_rom_polygon(points, show_controls=True)

bezier_shape = translate([3,0,0])(bezier_polygon(points, subdivisions=20))

See solid/examples/splines_example.py <https://github.com/SolidCode/SolidPython/blob/master/solid/examples/splines_example.py>__ for more details and options.

Jupyter Renderer

Render SolidPython or OpenSCAD code in Jupyter notebooks using ViewSCAD <https://github.com/nickc92/ViewSCAD>__, or install directly via:

.. code:: bash

pip install viewscad

(Take a look at the repo page <https://github.com/nickc92/ViewSCAD>__, though, since there's a tiny bit more installation required)

Contact

Enjoy, and please send any questions or bug reports to me at evan_t_jones@mac.com.

Cheers!

Evan

License

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

Full text of the license <http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt>__.

Some class docstrings are derived from the OpenSCAD User Manual <https://en.wikibooks.org/wiki/OpenSCAD_User_Manual>, so are available under the Creative Commons Attribution-ShareAlike License <https://creativecommons.org/licenses/by-sa/3.0/>.