Why LeoCAD

LeoCAD is a graphical interface, based on the LDraw graphical engine. With LeoCAD it’s possible, to create 3D models by stacking multiple (predefined) parts on top of each other, like playing with Lego.

Like LeoCAD, the LDraw system is designed to play with Lego virtualy. It has a massive library of Lego parts, which is also supported by many people. There are also 2 other main stream CAD editors, but I have choose to use LeoCAD, since it could be installed on 3 different operating systems.

The LDraw system is very well documented and basically I’m re-using this system for antique/vintage building toys, by simply replacing the Lego library with different parts, see picture:

How to make ‘use’ of the LDraw system.

In the LeoCAD menu -on top of this page- you find some basic information, how to install & use LeoCAD.

More information on tips & tricks will follow..

Work flow

I’m using this software workflow below, for converting old toys into the LeoCAD environment. There are quite some steps involved and it’s still fun to work on.

After deciding which game to add, it always starts with a search for available information. Sometimes there is already extensive infomation available, so it makes no sence to copy that in a different format. Once decided on a game, it’s time to collect all data like all unique parts, manuals & box content.

Once the parts are known, it’s time to create a unique part name list. Unfortunately parts numbers provided are not always handy/possible to use. Then it’s time to start a new 3D file and here I’m storing all parts with a 1:1 ratio. These parts are then exported as binary STL files. During this process it’s also good to know at what pitch distance the parts are used. Sometimes these parts have certain building pattern with is not handy to use in LeoCAD, so a scale factor is included.

The main library consists of these STL files and a big CSV file, containing all relevant data, including scale data, orientation and optional textures.

With a Python script it’s possible to convert these STL files into single LDraw files. If a planar texture file is used (in XY plane), these are automatically created too.

Once LeoCAD refers to the right libraries, 3D modelling could start.

The main library could also be exported to PovRay library, where part names are stored. Unfortunately textures are not (yet) possible. Once a model is created in LeoCAD, this .LRD file could be converted into PovRay by another Python script.

Since the LeoCAD part files have mostely unique colors, re-coloring of parts is (currently) not working, only the default part color is available. This has a negative side effect that exporting from LeoCAD to PovRay directly is not giving the right coloring.

The provided LDraw files should be used with LeoCAD, not PovRay. When animated files are needed, an amazing tool like ezgif.com could be used.