Compile Pure data patches with free online Heavy compiler

You can now use our online compiler to turn almost any vanilla Pure data patch into C source code. The service is free and open to anyone to use, built on open source projects, and you don’t have to be a customer or own an OWL to use it!

Since the beginning we have been using Enzien Audio’s Heavy compiler to turn Pure data OWL patches into C, which we then compile to optimised machine code for the OWL and Javascript for the patch library. Enzien Audio have now closed shop, but have very generously decided to open source hvcc, the Heavy compiler. Thanks to this we can still support Pure data patches for the OWL.

To make it easier for Pure data users to use Heavy and to provide continuity for existing Heavy users we have now extended our online compiler, so that non-OWL patches (ie general Pure data patches) can be compiled to C source. The C source can then be used to build VST plugins or integrate with games engines like Unity, Unreal or Wvise.

To use it, first create a free user account.

Next go to PATCHES, select MY PATCHES, and click CREATE PATCH.

Upload all the Pd files that form part of your patch. Alternatively you can add links to the files on GitHub, and they will be automatically fetched. Next make sure to select compilation type heavy. And if you have uploaded more than one Pd file, ensure that the correct file is selected as Main File.

You can now click Save and Compile, or just Save to be taken to the patch details page.

Here you can download the C source (if the patch has compiled), and add patch details in case you want to share or publish it.

If you want to add or remove files, or change the compilation type, click the + icon in the file tabs. If you compile it as an OWL patch, you will get a Javascript version which you can run in the browser window. And then you can run it on an OWL, too!

16 replies on “Compile Pure data patches with free online Heavy compiler

  • dreyes999

    Hi! Thank you so much for making this available online! Really appreciate it. I’m following this tutorial by Igor:
    And I notice that your online compiler does not build the Wwise Windows 64 bit target. So I cannot find these files:


    Can I be pointed in the right direction as to how to get these files? Thank you!

  • Martin Klang

    Hi there,

    initially we only supported the basic C target.

    We’ve now updated to support most targets: `c unity wwise bela fabric pdext vst2`
    If you recompile you will find that the download zip file includes all the target specific output as well.

    However our compiler doesn’t generate binaries, instead you will have to compile and link the output against the appropriate SDK on your target platform.

    hope this helps!


  • brian.hansen78

    Thank you very much for this! I teach a large class on game audio using PD, and I will definitely be directing everyone to this site.

    Currently I get an server error message window when trying to create a patch. It says
    “The string did not match the expected pattern”

    Could you assist with this error?


  • luka.loncaric

    Hi. When I try to save or save and compile pd patch with heavy, I get an error: Error Saving Patch – Access denied.

  • Igor

    Hi guys, just wanted to say thanks for reviving Heavy Online!
    I have added a link to this page on my Wwise/PD/UE4 tutorial!


  • markalanwagner

    I tried loading a simple delay pd patch, and see that it compiled to js, but don’t see the c++. Is it supposed to generate the c++?

    • Martin Klang

      Hi Mark,
      The C++ is generated behind the scenes, it is only made available for download when you select the Heavy compilation type.

  • nagaraj12121

    HI,When I generating C Code from puredata patches,It gives parameters with 0 values.
    How to generate c code with the parameters that we kept in pd design


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