# Pasta extrusion simulation

Hi all! I’m wondering what would be the best process to simulate a pasta die extrusion to play around with shapes.
I don’t think it would be a simple extrusion through the two shapes at the opposite ends of a die as the trajectory is probably influenced by the way those two shapes are aligned and how big they are… What do you think?

Fun question.
For twisted ones like fusilli or cavatappi you could use `Sweep 2 rails`

Some like penne you could do with simple extrusions, others like macaroni with revolves.

Actually simulating some of the more complex ones like farfalle would get pretty tricky though - there’s surely some non linear shell behaviour and plasticity involved.
Just modelling it would be easier though.
Now I’m hungry - time for dinner!

Unfortunately I’m not starting with a preconceived pasta type, just trying to come up with new shapes. The goal would be to use rhino to test a few die shapes and see what they produce

He showed an example, not assuming any specific profile.

So you draw your own (whatever shape) profile curve, and then Sweep along a rail.

// Rolf

I’m guessing that inside the die is generally just a short section of the 3d shape that comes out - so if the extrusion is twisted or curved, that’s because the die is twisted or curved. So you’d still need to model the 3d shape.
Something like the ruffled hyperbolic edges of campanelle does seem more complex though - maybe the mixture is somehow forced through at a different rate towards the edges.

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nice, i was inclined to drop a few coins for this book, but eh

\$1,060.00 currently

i am imagining it could also work if the die would be shaped that way, if it goes through a wavy tubus it would spill out that way. or maybe just the end of the die has a little nipple where the pasta gets friction and waves up

Indeed - it looks like it might work like this

this was also super interesting to me

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@DavidRutten made one tricky piece of pasta a while ago. Can’t forget that one…

// Rolf

I’d be happy to let you have my copy for half that.

Thanks for all the replies!
I think the way that pasta turns and the different “speeds” along the main shape are controlled by the dimensions of the entry and exit die holes. Ideally I am trying to have something that determines the shape once given the entry and exit shapes and the distance between them. So that I can experiment with shapes

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there are actually a bunch of fluid simulation software packages available, some built into general rendering and animations packages which even provide viscosity and friction. maybe you could experiment with such?

Yes, I’m currently looking into that

would a mesh growth algorithm work for this?
where the growth rate per edge is constant, but the number of iterations per edge is determined by the die in/out aperture ratio?

die aperture-in ratio = distances between red curves
die aperture-out ratio = distances between blue curves

probably accounting for the lateral trajectory of the die (green) is fundamental, otherwise you won’t get fusilli as helix, but just straight extrusions of their section

 recursive growth makes me suffer so much… this is with the help of a Kangaroo

close enough

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Fun question ahahah, I guess also the friction has a major role for the definition of the final shape and the exiting direction of the hole.

PS: I always wondered how in the world do they do the pasta with the hole? How do the piece of metal that goes inside the pasta piece is held in place if all around there is only pasta? I guess this is the best moment to try solving my ancestral doubts :D.

There is a cool demonstration on Youtube by PJ Chen called Pasta Forms 3D Modeling in Rhino 6 - plenty of shapes there. There is also a separate video dedicated to ravioli.