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A package for working with LDraw format files.

Project description

pyldraw Python Package

Author:rienafairefr code originally from David Boddie


LDraw is a standard format used by CAD applications that create LEGO models and scenes.

The pyldraw package provides facilities to allow users to create LDraw scene descriptions using the Python programming language. Pieces are specified by their positions, orientations and other properties in normal executable Python scripts which are run to create model files.

The pyldraw package includes code to have the complete LDraw library available to you through normal Python imports, like:

from ldraw.library.colours import Light_Grey
from import Seat2X2
from import Brick1X2WithClassicSpaceLogoPattern

The actual parts library hierarchy (in which subpackage each brick is, etc…), is still a work in progress. You can always specify parts by their LDraw code:

rover = group()
Piece(Light_Grey, Vector(-10, -32, -90),
          Identity(), "3957a", rover)


This is tested on Python 2.7, and 3.4+


The simplest way is through pip:

pip install pyldraw

Auto-generation of the ldraw.library.* package

The ldraw.library.* package is kind of special, it is auto-generated from a LDraw parts library ( with the parts.lst itself auto-generated using pymklist. On running code that needs something in the ldraw.library, pyldraw will know (through a sys.meta_path hook) and attempt to auto-generate it on-the-fly. Considering that the toolchain download, parts.lst generation, python code generation takes quite some time, and we don’t want to re-download anyway, the generated library will be cached and reused on subsequent import or python scripts run. If you setup another parts.lst or modify it, the library will be re-generated. The cached generated library is stored in the directory where the ldraw package is, if that’s user-writeable, otherwise in an OS-dependent cache directory (somewhere in ~/.cache for example)

  • Configuration

The parts.lst that is used for this generation is setup inside the configuration file (a simple YAML file) To get some info about where the configuration file is, use python -m ldraw.config You can specify where the library is generated by providing a library option in this configuration


A number of examples are provided in the examples directory. When run, each of these will write model information to the console. To create a model file from an example, redirect its output to a file.

Part Descriptions

Even though this package does include a list of parts derived from those supplied in the official LDraw archive, users can download or modify this list separately. The ldraw.library.* hierarchy will stay current with the LDraw database setup in the configuration

Parts are available from the ldraw.library namespace as described above, but you can also use the Parts class:

from import Parts
parts = Parts("parts.lst") # provide your custom parts.lst path

Parts can then be accessed using the relevant dictionary attributes of the parts instance. For example:

cowboy_hat = parts.minifig.hats["Hat Cowboy"]
head = parts.minifig.heads["Head with Solid Stud"]
brick1x1 = parts.others["Brick  1 x  1"]

Writers and Tools

The ldraw.writers package aims to provide a set of classes that write out LDraw descriptions in other file formats. Currently, it contains the povray module which provides a class for writing out LDraw descriptions as POV-Ray scenes.

The ldr2pov tool, uses the povray module to allow LDraw (.ldr) files to be conveniently converted to POV-Ray (.pov) scene files. Note that, since the LDraw format does not include information about camera locations, it is necessary to pass this information on the command line.

For example, on a GNU/Linux system, we can execute command lines like these to take the example file, create an LDraw model file (temp.ldr), and convert that to a POV-Ray scene file (temp.pov):

python examples/ > temp.ldr
ldr2pov /path/to/parts.lst models/figures.ldr temp.pov 160.0,80.0,-240.0
povray +Itemp.pov +FN16 +Otemp.png +Q6

Finally, POV-Ray is used to process the scene description and create a PNG image file (temp.png).

Some other tools and writers are included,

  • ldr2inv:

Transforms a LDR file into a file containing the Bill Of Materials or Inventory of the model

  • ldr2png

Renders the LDR file into a PNG file

  • ldr2svg

Renders the LDR file into a vector image in SVG


The contents of this package are licensed under the GNU General Public License (version 3 or later):

pyldraw, a Python package for creating LDraw format files.
Copyright (C) 2008 David Boddie <>

Some parts Copyright (C) 2018 Matthieu Berthomé <>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <>.


LDraw is a trademark of the Estate of James Jessiman. LEGO is a registered trademark of the LEGO Group.


This repo was extracted from the mercurial repository at

It will not try to stay updated with the upstream repo of the original author, David Boddie, The goal is to see what might be done, the original repo hasn’t been updated since 2011

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