export 3d model from Jitter GL (& import nurbs)

Feb 14, 2008 at 9:49am

export 3d model from Jitter GL (& import nurbs)

Hi people,

First time my max/msp/jitter issues can’t seem to be solved by simply searching this great forum, so here it goes…

I want to import an .obj 3d model (relatively simple surfaces, no texturing) in Jitter, modulate it by data extracted from audio sample analysis and export the resulting shape to have it 3d-printed.

My problem is in the last step: exporting. The jit.gl objects don’t seem to have any means of exporting to for example an obj file. Has anyone found a workaround?

Vade suggested I could parse the output of my jit.gl objects with @matrixoutput 1, save as a Jitter binary file and parse/convert to a 3d app readable format. Theoretically feasible but I probably can’t work this out in the given timeframe. Any other ideas?

Additionally, the surfaces I’d like to work with are nurbs but I understood Jitter can only import tesselated models. I could live with it but nurbs would be better. Any workarounds for that?

Thanks, Dieter

Feb 14, 2008 at 8:15pm

Hi Dieter,

I wrote a javascript that exports obj files from a matrix in jitter. I attached you an archive containing the script as well as a demo patch, which should demonstrate the use of the script.

Basically it just receives a jit_matrix and writes its contents into an obj file. If you need you can also define groups and materials for your object.

If you need any further explanation please feel free to contact me.


Feb 15, 2008 at 9:30am

fantastic! i’ll try it out over the weekend…

Feb 20, 2008 at 5:22pm

works like a charm… my eternal tanx to you!

Nov 7, 2008 at 3:57pm

Hi Dieter and Stephan,

I am glad I found this post. I am looking to do a similar project with max.
I have a couple of questions for the two of you.

Dieter, 1. how has your project progressed?
2. how much clean up did you have to do with your OBJ file before you converted to STL?

Stephan, 1. I have downloaded your zip but have not opened it yet, can the exporter work with jit.gl.sketch or does one need an object file to start with?

I am excited to read that others are working on this!


Nov 7, 2008 at 6:53pm

hi erika
i developed this app for a workshop with students. in the end they worked with the exported obj files. i guess it d be easy to convert those to stl using popular 3d modeling apps. i don t have experience with that myself.
from my memory (it s been a while) stephane’s script worked straight out of the box. no need for an obj file to start with either. i worked with a jit.gl.nurbs generating the model. i can send you the patches if you d like to have a look.

grtz dieter

Nov 8, 2008 at 5:16am

hi stephan.

really cool patch.
but one question: is there a way of reading a “obj.” back to your patch? the
idea would be to draw it using “line” or “line-strip”, etc and saving it
like that.
any clues?


On Thu, Feb 14, 2008 at 6:15 PM, spray wrote:

> Hi Dieter,
> I wrote a javascript that exports obj files from a matrix in jitter. I
> attached you an archive containing the script as well as a demo patch, which
> should demonstrate the use of the script.
> Basically it just receives a jit_matrix and writes its contents into an obj
> file. If you need you can also define groups and materials for your object.
> If you need any further explanation please feel free to contact me.
> stephan

Sandro Canavezzi de Abreu

Nov 8, 2008 at 4:00pm

Nov 9, 2008 at 4:20pm

Hey Dieter,
thanks for responding so fast, I have been looking at Stephan’s patch over the weekend and trying to get jit.gl.sketch to work with it. At this point I have built a simple line draw patch with jit.gl.sketch now the task is to figure out how to get the info into Stephan’s objectexport patch

I would appreciate it greatly if you could send me one of your nurbs patches, maybe it will be easier to understand to see how you worked it.

I am on a macbook pro OS 10.4.11 running MAX/MSP/JItter 4.6 jitter 1.6.3


Nov 9, 2008 at 5:17pm

Nov 11, 2008 at 7:07pm

Dieter, Stephan, and Sandro

By plunking in jit.gl.nurbs in place of gridshape, in Stephan’s patch I can get my nurbs object exported. I still have to figure out exactly if I can make the shape I want in nurbs, I am trying to draw a series of lines to make a shape almost like a nest. I did want to start from scratch that is why I wanted to use gl.sketch but I cannot figure out how to send my sketch data out to the matrix, I know that i have to use the glcommands but ????
still working I will post my patch soon if anyone wants to look at it.

Sandro, I think I am running into the same problem with the objects
I dont know if this helps but what I have been doing is exporting the object then using meshlab to look at my files, but they stay as solids even if i change the primitives for the objects. Again that is why I wanted to do it in gl.sketch

can one draw multiple lines in nurbs?

Nov 11, 2008 at 7:50pm

Mar 17, 2009 at 12:35pm

export 3d mesh from Jitter openGL matrix

great tool, I was about to try and make it, so glad someone told me this was here. I added those words at the top of this message so that it would come up if someone searches export OBJ 3d mesh like I did. I searched a few times and for some reason nothing came up, and it was because I didn’t say export 3d “MODEL”

at any rate, this is awesome, I cant wait to render out some of my jitter stuff in high res, or make a version of this that will do whole obj animation sequences!!

thanks so much!!

Nov 26, 2009 at 12:16am

Can anyone please post the example patch DIeter has posted, I cant find it here…

Thank you!!


Nov 26, 2009 at 5:54am

It seems that all the attached files are not uploaded to the forum yet, possibly related with the new site and the data migration they might be doing.
Maybe a little bit of patience

Nov 27, 2009 at 3:17am

Yes, Ive assumed that. Anyway I have it sorted thanks to kind help of Dieter.

Mar 16, 2010 at 9:22am

can anyone that has this patch post it here>? ive been trying to figure this one out for a while

Jan 24, 2011 at 6:14am

Bump! I’d also be interested in the obj exporter patch. Thanks!

Jan 24, 2011 at 7:08am

This may not have been the final version, but give it a go.


  1. objWriter.zip
Mar 15, 2012 at 8:47pm

Hey there

I’m also working on a similar problem,

I want to export the XYZ data from jit.gl.gridshape as a text file by using jit.fprint and I’m having some issues

I’ve attached a max patcher from max5 as an example

I’m going to be working on this problem further and posting the solution if I can find it, any help would be appreciated

  1. saveashape.maxpat
Mar 16, 2012 at 6:12am

Hey I figured it out , you can save vertex data out of this patch as a txt file and rename it to .asc and load it into whatever will take that format , I’m using meshlab

It was to do with carriage returns VS “line feed” , sending the message 10 to itoa to use a line feed was the answer

  1. saveashape.maxpat
Mar 16, 2012 at 4:53pm

Hi Sterling,
Thanks for sharing this, and for taking the time to work out the kinks.

Aug 11, 2012 at 5:43pm

Hi all (no Max for ages, nice to be back!)

After a frustrated waste of time trying to get an old c external of mine to work properly (trying to use glFeedbackBuffer – long story, everything coming out, but flat!) and now running out of time i’ve now switched to making some changes to jsobjwriter.js to fit what i need – specifically scaling, positioning (easy, done) and rotation (more chewy, working on it!)

I’ll share back the results here when done, but was just wondering if anyone had already done this – or can point to how to get the jit.gl.model objects i’m using to output the matrix with these transforms already on? (in which case i may be sick! ;)



Aug 11, 2012 at 7:09pm

Hey Jonny

My workaround to getting scaling, positioning & rotating was to just measure where the object was then add all of that to the matrix to offset it

I’ve attached an example to show what Im talking about, you could do the same in javascript if you needed

let me know what you come up with

  1. offsetshape.maxpat
Aug 13, 2012 at 6:56pm

hi guys. i just want to make sure you are aware that in Max 6, gl objects that support @matrixoutput 1 also support @matrixoutput 2.
matrixoutput mode 2 will apply ob3d’s transformations (position, rotate, scale) to the object’s geometry prior to matrix output.

Aug 13, 2012 at 6:59pm

I had not caught that thanks!

Aug 14, 2012 at 8:45am

Aaaaaaaargh! Would have saved me about 30 hours of headache! :) But thanks Robert, i was fearing there might be an easy answer, glad at least it seems to be an undocumented one.

Oh, and thanks Stirling for the trig pointers, what i got working eventually was based upon that.

Aug 14, 2012 at 3:27pm

Ah, of course that’s documented and i’ve been staring at it all week without understanding what “On With Transform” means – doh! :)

Aug 14, 2012 at 5:04pm

yeah some of the reference descriptions can be kind of technical.
don’t hesitate to ask the forum for anything that doesn’t make sense (documentation is an ongoing process).

Nov 19, 2012 at 9:34pm

Hi guys, I’m usually on the Max and MSP side of things, but for this project I wanted to adventure to the land of OpenGL and 3D printing. Little did I know…

What I’m trying to do is draw a curve and extrude it exactly like with [jit.gl.path] so that I can export an .obj to 3D print it. If [jit.gl.path] had the matrix output attribute I would be in heaven, but it doesn’t so I don’t know what to do. There are others here that tried, but it has been four years so I’m hoping things have changed :-) Is it doable using [jit.gl.nurbs] and [jit.gl.mesh]? Or maybe there’s a way to draw my curves with lots and lots of [jit.gl.gridshapes]? If so, is there a tutorial or example patch out there that could demonstrate how to do so?

I have scrounged the forum but with my limited knowledge of Jitter and OpenGL, I feel very very lost. I thought I found my answer with this awesome objWriter patch, but even though it has taught me a lot, I couldn’t figure it out. I would really appreciate it if someone could point me in the right direction.

Thanks for any tips!


Nov 20, 2012 at 12:34am

Hey Andrew,

Do you just want XYZ points or normals as well? Are you trying to create a solid form or just a thin path that has some depth to it? There are a lot of ways to approach this.

You could use jit.gl.expr and write the math in for what kind of curve you want then output that into a matrix and save that data to some file if you just need the xyz points. If you need normals it might be better to start with a gridshape or plato object

Checkout Meshlab http://meshlab.sourceforge.net/ for reconstructing points into solid forms

Nov 20, 2012 at 11:48am

Hi Sterling,

Thanks so much for responding. Just to clarify, I think I need the normals as I’m trying to create a solid form suitable for 3D print. Does this mean I need to use gridshape? If so, can I use it with jit.gl.multiple to create my curve? Sorry if I’m not asking the right questions, but this is new to me. My ideal scenario would be to be able to give XYZ coords, and a solid is created out of that. I really thought it would be that simple, right ;-)

If I send Meshlab my XYZ coordinates, can I make a solid out of that? To test, I tried creating a simple arc in Rhino and using “uniform mesh resampling” to give it volume, but with no luck.

Thanks again for taking the time to help.

Nov 20, 2012 at 7:05pm

Hey Andrew

You’re probably either looking at taking a gridshape and pushing the location of each vertex around based on wherever you want them. Or moving around an entire shape at small enough intervals so that its one interconnected thing. I’ve always written one matrix into a larger matrix multiple times using srcdimstart / srcdimend / dstdimstart / dstdimend rather than using jit.gl.multiple , either way would work I suppose.

I’ve also generated big clouds of vertices without normals and strung them together in meshlab with accuracy just based on the fact that I had so many of them in proximity. You could give that a shot then generate normals in meshlab. If your points all have normals the Remesh by Alpha complex shape works well from my experience , or you could try Remesh by Ball pivoting with/without normals.

I don’t really know what you’re trying to make, each approach has its advantages/disadvantages and would result in different things. If you’re just trying to create a few french curves for a single project you’re doing it might be easier to just use Maya.

It would be really nice if you could do matrix output on a jit.gl.mesh

Nov 20, 2012 at 10:21pm

Thanks, Sterling for all these tips. I’ll keep exploring with these options in mind.

Nov 22, 2012 at 1:21pm

Just to let you all know i did end up getting mine working thanks to the kind help of those here (thanks! :)

The object we created will be on exhibition in London from the end of this month onwards – more info at href=”http://www.londonfieldworks.com/projects/null-object

In the end i used a modified version of jsobjwriter.js, which i’ll try and attach here in case it helps anyone else. If needed i can try and make a help patch to show how i used it… if i get time.

Thanks all again!

Nov 22, 2012 at 1:24pm

(can’t get my head around how this forum works – there’s the help? ;)

Hopefully js file attached…

  1. jsobjwriter.js
Nov 22, 2012 at 3:23pm

Thanks Jonny. Can you briefly comment on what kind of changes were done to the original jsobjwriter.js file?

Nov 22, 2012 at 3:28pm

Hi Pedro
Can’t really remember but doing a diff of the original one posted here and mine it’s mainly adding transformations (pos, scale & rotate) and some stuff about colours (ambcolor, diffcolor & speccolor) but can’t remember what that bit was for as i wasn’t interested in colour for this project…

Hope that helps!

Nov 22, 2012 at 4:56pm


Nov 22, 2012 at 8:32pm

Hi Jonny,
would you mind posting a help file about your use of the jsobjwriter.js file? thanx in advance.

Jan 20, 2013 at 4:18pm

Hi friends

I’ve been revisiting this issue and I modified jsobjwriter.js to support the tri_fan , quad_grid and tri_strip primitives in a way I think is more accurate to the way Max/Jitter tends to render generative 3d files. I’ve also commented out some of the behavior in regards to the way it accepts messages about which primitive it ought to use, because it had this tendency to ignore what I was asking it to do.

The new primitive modes are accessible as tri_fan2 , quad_grid2 , tri_strip2 . I may work through all of them at some point but those seemed to be most useful ( or at least the ones I wanted ) .

You can find the file here with an example patch https://github.com/sterlingcrispin/public/tree/master/max

After exporting I suggest using Meshlab to clean your object. Sometimes very long edges are produced between ends of objects which are undesirable.
Filters > Selection > Select faces with edges longer than ….
Filters > Selection > Delete selected faces and verticies


the following screenshots show max (left) and meshlab (right) , not particularly interesting shapes but they’re highly nonconformal and essentially random vertices/faces as a proof of concept. If you’re having troubles with normals , you can usually generate them in meshlab with some success.

[attachment=212855,4918] [attachment=212855,4919] [attachment=212855,4920]

  1. ScreenShot20130119at8.59.21AM.png
Jan 20, 2013 at 7:13pm

thanks a lot a lot a lot ,
this will save me so much time !

i have just made a try with the basic sphere, but reloading the obj. in BLENDER ,
i get the sphere sliced in 22 discs(+2 points at xtremities) ,
don’t know if this is expected , …
just to let you know ,
i try to join a screenshot .

thanks again , i have not read the thread , just discovered it right now ,
i’ll find this functionnality extremely useful , for sure

  1. blendercapture.tiff
Jan 20, 2013 at 7:30pm

Thats what it looks like in max under the tri_fan primitive , as shown in this screenshot. Unless I'm on some kind of freak-mutant version of Max that no one else is experiencing. Try navigating around the sphere in 3D within Max, it should look like that 22 disk view.

I built the tri_fan2, quad_grid2 and tri_strip2 to mirror how things appear in Max, but there can be discrepancies. Play around until you get what you're after. If you want a solid object just use quad_grid or tri_grid , change the draw_mode from within Max , then set that as the same primitive on export and see if you're getting the results you expect.


  1. ScreenShot20130120at11.17.52AM.png
Jan 20, 2013 at 8:13pm

now i get it
i like the tri_fan2 style …

Mar 6, 2013 at 8:12am

HI. thank you very much for the script post in the toolbox area here:


It was the first one I was able to get working:) I think the issue with the tri_fan etc, probably caused the sphere to appear as in the attached image. The problem is, as I see it, is that the order of the points expected to construct solids from a mesh can vary from one 3D environment to another. that is, not all the solids shading options are necessarily consistent. Also there is a secondary issue, that is smoothing and creasing is adjustable on Carrara import. I don't knmow for other programs. However it's a real accomplishment nonetheless, and I'll share the capability in the Carrara forums :)


  1. Capture.JPG
Mar 6, 2013 at 7:01pm

I have never used Carrara, but the idea of the OBJ format is that its supposed to be universal. Does Carrara actually ask you what primitive the OBJ is when you import it? Correct me if I’m wrong but OBJ’s dont actually contain explicit information about the primitives used, and can use any arbitrary method of stitching the vertices together. Its just a list of vertices and then a list of how they should be connected.

Try downloading Meshlab http://meshlab.sourceforge.net/ and opening your OBJ file from Max in that. If you’re still getting the same results than you’re probably sending data in the wrong shape or format to the exporting script. Check your plane count dimensions and data type. Or try tri_fan2, quad_grid2 or tri_strip2, play around with primitives and your geometry. You should be able to get something that gives you the results you want without much trouble.

Mar 28, 2013 at 12:42pm

Thank you very much sterling!



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