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Using Modalys finite element method engine to build reverberations

A good old idea…
Has anyone tried to build reverbs using finite element ?
Would Modalys work for that or it is completely another story ?

How would you do ?
— Building an object made of a specific material.
— Filling it with another material : air.
— Connecting the two. I think this may be the hardest part with Modalys…
— Placing a listening point and a pluck connection inside the air object.

Thanks !


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Hi, @pasquet,

I’m not entirely sure if I’m following what you want to do here, but, as far as I understood, I guess you could try something like this Max patch made by @lochard Rubbing? and meshes in MAX . Here, he made a mesh object in ModaLisp, in which one could define the material properties of said object, computed the modes of it and saved it in a file and opened in Max with the <mys.read-from-file> object and have the mesh object resonating to any signal input.

I don’t know if you’re interested in the ressonance of the mesh-object itself (in which case, this solution might work for you) or in the ressonance of the space created inside the object, in which case I would guess Spat would be a better tool to work with?

In any way, not a Modalys expert here, hopefully someone with more experience can give some input on the matter

Hi Olivier !

The problem here is that you need the resonance of the air IN the mesh. Finite-elements will give you the naturals modes of the object itself…so it is seems difficult to build an Impulse Response with Modalys.



Hello Raphael and Jean !

Thank you for your answer !

@lochard Rubbing? and meshes in MAX is very good indeed. But it uses one only material and I am looking for a way to make an access within the object filled with air.
I was wondering if it was possible to:

  • have nested different materials (concrete and air for instance)
  • adhering them together in some way (adhere connection ?)
  • have access inside the two objects

According to the documentation for finite element technique, Modalys locates the closest point on the mesh relative to the one defined by the 3 coordinates given in the controller. So I guess it is not possible to access inside.

Thanks !

Hi @pasquet,

“Has anyone tried to build reverbs using finite element ?”
My answer is a bit off-topic (out of modalys world), but keep track of this new research project RASPUTIN: https://www.ircam.fr/projects/pages/rasputin/
As far as I know, building reverbs using ray tracing as finite elements would be a by-product of the project. Maybe somedays in the future of spat ?


Hello !

Ray tracing or anything else as as finite elements, from meshes.

That would be tremendous. An old dream would come true ! In the meantime, I have an idea and will quickly do something whenever I get the time.

Trying to generate IRs from Modalys would allow the use of meshes for both room and instrument simulation. Some sort of continuum between bodies’ definition. Imagine being inside a wooden room with iron replacing the air.

Unfortunately again, I do not see how I would connect a body mesh with an air mesh. And moreover, I think it is not possible to create a Modalys access inside the mesh. It seems to only be possible to place it at the surface.
I am wondering if I am right or not…?

I would otherwise implement Modalys into Rhino for multipurpose tasks; in a quick, productive and dirty way as usual.
(For your information, there is already PachydermAcoustic as a lib for Rhino but it is not quite the same idea and I think it does brute-force ray tracing.)

Romain Michon in his Faust Physical Modeling Toolkit made a mesh2faust command.
It is really great but from my experience it apparently gets the same limitations for access position.


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