Computational geometry in jitter…

Jan 31, 2009 at 7:22pm

Computational geometry in jitter…

I would like to explore the use of computational geometry in
Max. Of course Jitter has many features for doing this.

The ultimate goal is to process geometry in jitter and
create scores with it. The geometry does not actually have
to be created in Max, but it would be processed and converted
into meaningful control data.

Before I go off creating such things, I like to check if there
are already existing tools that do that. I was wondering if
someone out there knew of a tool that exists that allows me to
easily create geometry, for example a decaying spiral helix. It
would have to be in a format that jitter would be able to load of
course.

Any feedback would be appreciated.

Thanks,
Anthony

#42030
Feb 3, 2009 at 12:35am

Surely someone in jitter land has tried this…
Anyone?

#150166
Feb 3, 2009 at 1:20am

On Jan 31, 2009, at 11:22 AM, Anthony Palomba wrote:

> I was wondering if
> someone out there knew of a tool that exists that allows me to
> easily create geometry, for example a decaying spiral helix.

Check out: jsglsurface-example.maxpat in the Jitter examples. There is
exactly that in the “Spiral Shell” which was adapted from paul
bourke’s page:

http://local.wasp.uwa.edu.au/~pbourke/geometry/

Lots more on procedural geometry there…

-Joshua

#150167
Feb 3, 2009 at 11:07am

you can make a spiral in a lot of 3d packages, maya, cinema 4d, 3d studio max, and others. You can load the model in jitter with the jit.gl.model object.

The best thing to do though is probably make the geometry in jitter, so you have the most control. It Shouldn’t be that hard to find an equation to make a spiral with a jit.gl.mesh and some jit.expr or something like that.

Let me know if you make any advances.

#150168
Feb 3, 2009 at 3:54pm

It is not so much an issue of finding the equation of a helix, it
is about having a tool that creates any kind of geometry I want
with out having to waste time finding the formulas.

Trying to rebuild applications like maya, cinema 4d, 3d studio max
in jitter would be an impossible amount of work for just me alone.
Ideally it would be great if someone knew of a free application
that generates geometry in a format that Max can load.

#150169
Feb 3, 2009 at 4:47pm

On Feb 3, 2009, at 7:54 AM, Anthony Palomba wrote:

> Ideally it would be great if someone knew of a free application that
> generates geometry in a format that Max can load.

Anything that generates OBJ files. On the free front, I can recommend
Blender, and here’s a nice site found by the simple google search free
“3d modeling applications” OBJ.

http://www.hongkiat.com/blog/25-free-3d-modelling-applications-you-should-not-miss/

-Joshua

#150170
Feb 3, 2010 at 2:48pm

Okay, I am bringing this thread to the surface again because
I have another question. So after a long hiatus, it is back to
working on this problem…

So after investigating things, I was able to create geometry in
an external 3d editor and load it in Max using jit.gl.model.

What I really need to be able to do, is to get accesses to each
vertex so that I can map that value on to some musical parameter.
I then want to play through that data at some constant rate.

Does anyone know how I could access the models data once it is
loaded in jitter? Also, if I wanted to create a generic buffer
of vertex data that I could then manipulate, what would I use?

#150171
Feb 3, 2010 at 3:13pm

You can get the vertices from the .obj file directly, any line with a “v” and three floating-point numbers is a vertex, it’s a nice clean format (at least in my examples it is). Likewise for the facets with “f”. Read the file into a [text] and spit out the values with the line $1 command, then maybe load these lines into a jit.matrix (jit.fill) for more funky processing. I think to see the results in real-time you’d need to send the full jit.matrix to the vertex inlet of a jit.gl.mesh object, separate from your jit.gl.model.

Could be very interesting with some standard “video” effects applied to the matrix of vertices, before rendering it again… and then your choices of what to do with it audio-wise are pretty endless as you know, especially with some scaling or further transformations.

I don’t know whether jit.gl.model lets you get at the vertices specifically.

#150172
Feb 3, 2010 at 5:26pm

If you are looking for applications that model directly based on the formula, you should check out this page:

http://www.subblue.com/blog/2009/5/14/fractals_and_generative_art_resources

Structure Synth is probably the one to check out.

As for getting vertices, you can use @matrixout 1 on the GL models, and then upload that to jit.gl.mesh, but also ‘intercept’ them for analysis on the CPU side. This will give you the raw matrix (plane 0 = x, 1 = y, 2 = z) and you can go to town using the msp bridge objects poke/peek to get them to audio land, or just unpack and convert to midi, or whatever.

#150173
Feb 3, 2010 at 5:26pm

@matrixoutput 1

#150174
Feb 3, 2010 at 10:09pm

Ah, of course. doh.

I also really appreciated the list of freebie 3D apps posted by Joshua. I’ve got a handful that look really fun to try, especially the K3DSurf one for math models. I’m sure I’ll wish some generated number streams could get into its number boxes just like we do all the time in Max…

If a 3D app works well for someone but it doesn’t output .obj, AccuTrans can probably convert it for you:

http://www.micromouse.ca/

#150175

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