3d mesh with discrete force mapping

May 13, 2013 at 10:30am

3d mesh with discrete force mapping

I have a 6 x 3 force-sensor matrix connected to Max and I would like to visually represent the 18 discrete and dynamic streams, something like Randy Jones has for his digital tabla here:

Perhaps there’s even something lurking on the jit.phys helpfiles or examples I could tinker with.

Many thanks


May 13, 2013 at 10:31am

link didn’t post:

May 13, 2013 at 10:32am

aw fer feck’s sake:

May 14, 2013 at 12:01am


– Pasted Max Patch, click to expand. –


May 14, 2013 at 2:06am

Hi Wetterberg
many thanks for this; am I initializing it correctly? I hit the loadbang, set the z-plane scalar then start the metro and I get a grey box with elongated polygons:

  1. mesh
May 14, 2013 at 7:44am

ah yeah, I keep forgetting to initialize the parameters in the attruis (I really don’t like that way of working, you can’t control them properly etc)

Lemme real quick set up the @’s and I’ll re-up.

May 14, 2013 at 7:51am


– Pasted Max Patch, click to expand. –


May 14, 2013 at 9:10am

Just emailed you Brendan, but here you are, something with jit.gl.nurbs. You could set up 18 of the nurbs objects like in this patch and position them or if that’s not too efficient (not sure) you could do it all with one big nurbs, but controls might get complicated!



– Pasted Max Patch, click to expand. –


May 14, 2013 at 9:49am

Thank you gents.

I’ll tinker away at these, attempting to duplicate and offset positions for each nurb via the [attrui] to [jit.gl.nurbs]; I will return here if I encounter any issues with [jit.noob]


May 14, 2013 at 10:22am

I think the problem with the setcell method is that it overrides the lovely snorm work that goes before it – it’ll move not just the z, but also reset the x and y for any incoming data to 0,0.

Perhaps combining the two examples is in order?

May 14, 2013 at 11:39am

how about this?


– Pasted Max Patch, click to expand. –


May 14, 2013 at 1:01pm

Thanks Wetterberg, the idea of using a physical surface is attractive, I particularly like the ability to distort or disturb a plane or virtual sheet in discrete locations in this way. But tweaking the coordinates and physics of such an approach would be beyond the time I have available sadly, so I’ll go with Luke’s suggestion solely because I can adapt it quickly to my exact needs. I have created 2 discrete nurbs meshes with independent distortion (which will originate from the FSR input to Max) and I will now just steam ahead and repeat the process for all 18 sensors. I’ve posted it below in the hope that either of you will glance at it and think either “yeah, not bad go for it” or “DUDE!! You CANNOT do this, because….”


– Pasted Max Patch, click to expand. –


Thanks again

May 14, 2013 at 1:04pm

I’m very curious, what’s the sensor grid comprised of?

May 14, 2013 at 1:09pm


I have built a customized and accessible control interface (for performers with cerebral palsy) using 18 DIY force-sensors (copper, Velostat, silicone rubber and ultrabright LEDs); the signals are mapped to a string model, a novel granular playback synth and a simple FM synth. With some very exciting performative mappings.
Coming soon to a conference near you :¬)


May 14, 2013 at 1:35pm

well well well!

Uhm… if you ever… uhm… need… ablebodied testers…

Duplicating the nurbs out seems valid, especially since it’s only 18 you’re dealing with. Also, it’ll make it easier to apply brightness changes to each zone individually. It’s simple, and it’ll work, from what I can tell.

May 14, 2013 at 2:16pm


It would be a bonus if the instrument found favour with both disabled and non-disabled performers alike, so perhaps I’ll “use” you when my PhD is done……….future work, and all that.

I’m finding the duplication process really laborious, as my maths stinks. If my first (lefthand) column consists of the following position attributes:
-3.75 -2.65 -7. (bottom left)
-3.75 -1.65 -8.75 (middle left)
-3.75 -0.65 -10.5 (top left)

what is the quickest way to plot each subsequent row to the right? Simply retain the second (changing) pairs of coordinates and shift the first X coordinate?


May 14, 2013 at 2:58pm

At any rate I’m looking forward to hopefully getting my hands on your written work for this down the line.

yeah, if the nurbs is exactly 1 unit big, then shift by 1. Yeah, that’s like the one reason for using a single big mesh, but it’s also pretty much a set-and-forget thing, I’d assume.

May 15, 2013 at 2:36am

Works a treat:

May 15, 2013 at 3:30am

Hey, looks nice, can’t wait to see it hooked up for real!

May 15, 2013 at 10:05am

real nice. Looks exactly like one big mesh.


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