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Add-On: Molecular


Jean-Francois Gallant announces the release of the beta version of Molecular.

Jean-Francois writes:

I want to share with the community the announcement of the beta version of my addon: Molecular. After 2years of research and developpement for fun, with not a lot of time to put on it , I finally got something interesting and usable by everyone. When I start play with it , for people don't follow me from the beginning , I rewrote the script probably 4-5times by changing my approach due to some limitations. But now it's completed and rewriting it with Cython make it multithreaded and faster ( a gain of 30 times faster than python version ). Now what Blender need is a good particles mesher and MohamedSakr (from ) already start to work on it.


About the Author

Avatar image for Bart Veldhuizen
Bart Veldhuizen

I have a LONG history with Blender - I wrote some of the earliest Blender tutorials, worked for Not a Number and helped run the crowdfunding campaign that open sourced Blender (the first one on the internet!). I founded BlenderNation in 2006 and have been editing it every single day since then ;-) I also run the Blender Artists forum and I'm Head of Community at Sketchfab.


    • Many peoples told me the linux version of the python extension should work. I don't have access to a MAC but if somebody can test it , let's me know about the result. If not working , the Cython pyx source code is available to be compiled. ( I can provide the C file generated by Cython too )

      • I'm on a Mac too.
        I've added the Linux_64 add-on into the Blender Scripts folder.
        It appears in the list of Addons, but it is impossible to check the box to activate it!
        Shame - the vid above looks amazing.

      • OS X 10.8.3 MBP, blender 2.66, the add-on just doesn't appear in the list. I have no idea how compile it, if somebody do that could share with us? I really want to test this add-on, looks amazing!

    • I contacted Jean-Francois and made a 32-bit build. It seems to work on my end, though I haven't tested on any other machines. It's up for download at Just unpack the .zip and place it in your addons directory. Hope it'll work! =)

      • Thanks Senshi !

        I will try to support it soon to don't have to ask you to build everytime I did a fix on it ;o) I currently trying to create a virtual machine with osx white leopard on virtualbox. For now , if you want , I can put the zip on my blog with a credit mentionning your name :)

  1. I can't activate it ! :(
    When I choose install from file, the add-on doesn't show on the list then. I can't see any errors in a terminal, though.
    (Linux Mint 13 64bit, Blender 2.66a)

    • What the "install from file" does is to unzip it in "[your blender installation folder]\2.6x\scripts\addons". So unzip it here and make sure you the "[your blender installation folder]\2.6x\scripts\addons\molecular" with and in it.

  2. polygonesrus on

    a few months ago is this script when i saw it in the upload tracker . is this a rewrite of that one, an upgraded script. dont want to get the same script again . by the way great add-on.

    • Not the same for sure. I rewriting it in C ( cython ) so it's 30times faster than my pure python version. Many features is added in the last week too , so it's not the same you already have.

      • polygonesrus on

        wow cool , thanks for the reply :)))) . this is a big day,my first answer on any blender related forum . woho. and cant wait to give the new script a try .

  3. I have a problem with the Windows 64 bit version of it. I'm testing some of the given files, and the plugin doesn't seem to be affecting anything. The particles just fall.

    All settings untouched from the demo files.

    • Hi there,

      same with me - downloaded it, installed it, it appears in the list and can be checked. But when I play the demo files all particles just fall down to the ground. It's Win 7 64 bit.


      • Me again, I'm so sorry... guess I need more documentation on this addon. I just saw the button "Start Molecular Simulation" on the right side... now they don't fall down anymore and I will wait for the result. Thanks so far for this addon!

  4. This fantastic tool goes right to an idea I had few years ago. The 3d world is a world where everything is hollow. Delete one single face of an object and you can see that it's empty inside. It is a world made by flat polygons.

    But if we made 3d objects with 3d atoms and molecules? Until now, the most close of this was particles. Blender smoke, for example, is not hollow. We can navigate through it.

    A 3d world made of atoms and molecules would be a totally different 3d world, more similar to the physical world. It would be a revolution. Is this amazing tool the begining of the revolution?

  5. The first time I got the idea is in 1998 , with the game/program call Really ! near the same things but in 2D. After that I got to school to learn 3D and always keep in mind to doing the same things in 3D. When I see Lagoa Multiphysics , it's just to give me the push to trying to do the same things. I choose Blender at home because I follow it about couples of years and I'm always impressed all what it's does update after update. Unfortunatly I never use on a production , use more XSI or Maya. But slowly , I convince and impress colleguse with Blender capabilities.

    NOTE: Unfortunatly , OSX are not supported for now. I need to find a way to compile it. For linux I use a virtual machine with virtualbox ... I can try if I can install OSX on a virtual machine and compile the addon.

  6. Nicolas3DPL on


    Really good add-on for blender. Unfortunately it seems to have bug: sometimes (rarely) when I press "start molecular simulation" script closes blender and I can't do anything. I don't know why. Anyone has the same problem?

    • Yes I know this problem. I try to fix it. It's why the addons is in beta stage. If anybody have a blend file that crash each time or near when you press start , send it to me ( wrote me a email in contact tab of my blog , I reply back to give you my email and send me the blend ). I have difficulty to fix this bug because like you say , it's append rarely :( Until I find it, save your blend before you press start to be sure. It's never crash when you press it for the first time in a fresh new blender , it's happen when you did it again and again.

  7. why it doesnt work for me,when i install it i ant activate it,whats th problem,or it need cython maybe,becouse i dont know how to install cython :/

    • You don't need anything ( cython is for dev ). Did you follow the instruction in the docs for installation? Did you try the alternate installation ? What did you mean when you said it's not working. You see it in the addons tab but you can't activate it ? Give me more details. :)

      • After I Install it,i just cant click the check box
        i have already tried the alternate installation,i still cant click the check box of the addon

        Im Using
        Windows 7 Ultimate
        Blender 2.66a
        Acer ASPIRE 5738Z
        Intel Pentium 2.2GHz,800 MHz FSB
        2 GB RAM

        Here, I Uploaded A Video

        • I see you video and the only thing is missing is show the console at the end. After you trying to click for activating it , did you get a message in the console ? If yes , send me what it's appear .... if nothing, try this:

          Remove the folder Molecular in : C:\Users\[User]\Appdata\Roaming\Blender Foundation\Blender\2.66\scripts\addons\

          and make sure molecular.pyd and don't exist at the root of this folder too. Do the same thing for the folder D:\Program Files\Blender Foundation\Blender\2.66\scripts\addons

          After you are sure all is deleted , retry it.

          I retry to install it on my system ( 32bit version ) right now in the way you did it in you video and it's working for me. Hope you have some error in your console to help a bit or the cleanup make it working.

          • It gives an error about not finding a DLL. I'm not sure how to copy the console.

          • numanair:

            You use Blender 2.66a with the good version of the plugins ? I mean ... if you download the windows 64 bit version of the plugins you need to use it with Blender 2.66a windows 64bit.

            Because this error it's look like it not be able to load my python module and I just see that when:
            1- architecture 32 or 64 is not the same between blender and module.
            2- Python version used to compile the module ( 3.3 ) and the one use by Blender ( 2.66a use 3.3 ) is not the same.
            3- Some manifest error when I compile it with MSCV ( but it's not the case , I tested both windows addon version ).
            4- Don't use the right addons version for the right operating system.

            I redownload the addon on my website and I test it on both Blender 2.66a version (32 and 64bit) and it's working fine. You are the first case of someone reporting it's not working on windows or linux. It's harder for me to test OSX because I don't have this system installed correctly for now.

          • Hi PyroEvil,

            I also cannot activate the addon on Windows 32bit.

            I'm using version 2.66a (2.66.1 r55075:55077) on Windows 7. It's the ZIP version. I am using the 32bit version of Molecular. I've made sure that and cmolcore.pyd only exist in one location (in my case D:\Graphics\Blender\blender-2.66a-windows32\2.66\scripts\addons\molecular).
            I can see the addon in Blender, but I cannot tick the box.

            Here is the error from the console:

            found bundled python: D:\Graphics\Blender\blender-2.66a-windows32\2.66\python Traceback (most recent call last):
            File "D:\Graphics\Blender\blender-2.66a-windows32\2.66\scripts\modules\", line 269, in enable
            mod = __import__(module_name)
            File "D:\Graphics\Blender\blender-2.66a-windows32\2.66\scripts\addons\molecular\", line 32, in
            from molecular import cmolcore
            ImportError: DLL load failed: The specified module could not be found.


          • thanks for the details bigceef. Weird I don't get feedback from more peoples with this problem. On my side I don't be able to reproduce it. I investigate that soon I can for sure !

          • not sure it's solve the issue but try that:
            -1 Open
            -2 At line 32 where you see "from molecular import cmolcore" replace it by "from . import cmolcore"
            3- save it
            4- try to activate the addon

          • PyroEvil:

            I tried your suggestion but that didn't fix it unfortunately. I get the same error (but showing '.' instead of 'molecular', obviously).

            Thanks for the suggestion.

          • I recompile the addon , make sure no permission is apply on it , remake the zip file and upload it again on my blog.
            So people with problem with windows32 and windows64 can retry it ? ( delete old addon , redownload the new and reinstall it )

          • It's still giving the same error about not finding the DLL. I think it has to do with the extension being .pyd

          • I mean not specifically because it's a pyd, but because of the way python looks for pyd files.

          • Yes but if it's the pyd the problem, why it's working on my 3computer I have and probably on many computer of other user ? I really don't understand why I cannot reproduce this problem.Can you give me this info:
            -Blender version:
            -Addon dowloaded:
            -Python installed?:
            -If python installed, which version:
            - Operating System(32/64bit, home/professional edition ...etc ):
            - CPU:
            - Memory:
            - Video cards:

          • ok I have something you can try:

            A cython user tell me it's about dll dependency.
            You are missing some common dll in your Windows install that not coming with Windows by default.

            He recommend me to use to see which DLL is missing. So if you want , download it , run it and open cmolcore.pyd with it ... and see what happen. On my side it's just flags two missing DLL but I think it's normal because I don't run it in Blender. python33.dll and VCOMPP90.dll . See if it's missing more on your side.

            thanks a lot

  8. Wow, looks great. If Blender got a fast and accurate particle mesher, this could be very, very, very, exciting! Even as is, this opens up quite a lot of possibilities.

      • Can you give me the entire log from the beginning in your console ? I put some output informations to trying to solve this issues.

      • ok I have something you can try:

        A cython user tell me it's about dll dependency.
        You are missing some common dll in your Windows install that not coming with Windows by default.

        He recommend me to use to see which DLL is missing. So if you want , download it , run it and open cmolcore.pyd with it ... and see what happen. On my side it's just flags two missing DLL but I think it's normal because I don't run it in Blender. python33.dll and VCOMPP90.dll . See if it's missing more on your side.

        thanks a lot

  9. I have a little problem. I'm working on Mac with system 8.10.4., Blender 2.68. After installing add-on and setting up simple particle system and pressing Start Molecular Simulation button I get in return an error:

    location: : -1
    Name Error: global name 'cmolcore' is not defined
    mol_report = cmolcore.init (mol_exportdata)
    and so on.

    Maybe I do something wrong?
    Google doesn't find solution :)

    • Mac version doesn't work , I'm gonna go to remove it until I got somebody to fix it. I don't maintain this version myself because I don't have a mac to compile it. sorry :(

  10. I can't get my addon to work. Whenever i click start on the bake it gives a strange error....then won't give the option to bake anymore.

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