LSynth 3.1 for Mac OS X

I have compiled a Mac OS X version of LSynth 3.1, the recently released update to the program that synthesizes LDraw code for flexible LEGO parts.

Download LSynth 3.1 for Mac OS X 10.5+ (Universal Binary; 85 KB)

This download includes the lsynthcp executable as well as the configuration file (.zip) and the constraint parts (.zip) available at Willy Tschager’s installation tutorial page for MLCad users (which contains some useful information for all LSynth users).

Important Compatibility Note: The executable in the above download may only work with Mac OS X 10.5 (Leopard) or greater. Click here to download a version of lsynthcp that should also be compatible with Mac OS X 10.4 (Tiger), provided by current LSynth developer Don Heyse. Thanks, Don!


Copy the LSynth constraint parts to the parts/ or Unofficial/parts/ directory of your LDraw part library. Keep the lsynth.mpd configuration file in the same directory as the lsynthcp executable. LSynth is not integrated with Bricksmith, so you can keep these files wherever you prefer. You will need to use the command line to run LSynth.


To use LSynth, you manually place constraint parts at key locations such as the endpoints of a hose. Then you input the LDraw file to lsynthcp, which generates a duplicate file containing all the hose segments, chain links, etc. necessary to represent the flexible part described by the constraints.

For example, here is the RUBBER_BAND-Constraints.ldr file from Willy’s excellent page of LSynth examples:


With the file in same directory as lsynthcp and lsynth.mpd, run the following command:

./lsynthcp RUBBER_BAND-Constraints.ldr Rubber_band_output.ldr

Here is the output:


For more detailed information about using LSynth, peruse Willy’s troubleshooting page and the pages linked above.


Here are the minor modifications I made to compile the LSynth 3.1 source package for Mac OS X:

  1. Edit the comment on Line 69 of lsynthcp.c to begin with slashes (//) instead of backslashes (\\).
  2. Append “-arch i386 -arch ppc” to lines 3 and 17 of makefile to enable Universal Binary support.

The make command is sufficient to compile the program.

This release supersedes the LSynth Service I made a few years ago.

Posted on Saturday, November 21st, 2009. Tags: , , , .