Forums > Beginner Poi Moves > The maths of the 3 Beat weave

Hi all

Recently i've been working on a 3D-animation coursework within which i decided to add a person doing poi. Course its all rather simple...the poi are made of a cylinder and a sphere and the "person" spinning them is a collection of cylinders to make the arms.

To do it i had to figure out the maths behind the 3 beat weave. Once i got into it, it became rather complicated to think about , its amazing how the simplist things our bodys can do are so god damn strange to model in maths and on computers. It turned out to be rather interesting if you're into that kinda stuff . Thought id slap it on here see if anyone was interested

I decided to model the situation on a per-poi basis to simplify things. Each poi has their own period which raises in steps of 10 degrees and has a range of 1080 degrees (that is 3 full rotations).

Now the things which make it a 3 beat weave is the points in this period where the poi travels from the left hand side to the right hand side and visa versa. I worked this out as being:

left poi
---------
leftPoiRotate >= 990 || leftPoiRotate <= 90
left poi travels to the left

leftPoiRotate >=270 && leftPoiRotate <= 450
left poi travels to the right


right poi
---------
rightPoiRotate >= 990 || rightPoiRotate <= 90
right poi travels to the right

rightPoiRotate >=270 && rightPoiRotate <= 450
right poi travels to the left

What this gives you is 2 poi spinning, changing position in x to give the affect of the 3 beat. To get a better 3 beat you can also add the change in period of the y which is simply the y portion of a circle at any given period of the poi....something like:

y = sin(poi_rotation)

The time steps the poi remain on the right or left hand side is what gives the movement of the 3 beat. With a bit of tinkering i recon this could be boiled down to a couple of paramteric equations for x,y and z for each poi

Hmm, but yeh thats what you're doing when you spin a 3 beat ...or a close approximation where the arms pass through each other anyways

Efficient humour: "heh...wang "

Written by: Richee

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NYC: What is TI-83?

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Well, shall we go?
Yes, let's go.
[They do not move.]

Written by: NYC

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Shouldn't be manic. It looks like a fish swimming to the right. The graphing calculator is nice because you get to actually see it follow the path.

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Love is the law.

POI THEO(R)IST

"i see you at 'dis cafe.
i come to 'dis cafe quite a lot myself.
they do porridge."
- tim westwood

Written by: mcp

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PICTURES!!!!!

please sir, can we have some pictures... (or maybe a video?)

:tantrumsmiley:

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Well, shall we go?
Yes, let's go.
[They do not move.]

Efficient humour: "heh...wang "

Efficient humour: "heh...wang "

Well, shall we go?
Yes, let's go.
[They do not move.]

fire is just light and heat.
it's you friend!

Well, shall we go?
Yes, let's go.
[They do not move.]

fire is just light and heat.
it's you friend!

Let's turn those old bridges we crossed into ashes.
We'll blaze a new trail,
and torch the rough patches.

-Me

Efficient humour: "heh...wang "

"the now legendary" - Kaskade
"the still legendary" - Kaskade

I spunked in my friend's aquarium and the fish ate it. I love all fish. Especially the pink ones. They are my bitches. - Anon.

passing through, this world still lives.

Written by: Frodo

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i can see it.....

Lovely... now for the butterfly... lol

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Well, shall we go?
Yes, let's go.
[They do not move.]

Efficient humour: "heh...wang "

Written by: sinjax

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Hmm myself and puresock were talking about this and indeed wraps would be hard to model this way

I thought maybe modeling the poi accuretly? as apposed to a single point spinning, have each section of the poi have its own path to follow (which is in essence what makes the wrap possible)...

so periodically a section of the poi would change equation. Course this method would be just conditional logic on the T value and not a nice tidy clean function like the one you created for the weave

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"Moo," said the happy cow.

Well, shall we go?
Yes, let's go.
[They do not move.]

Well, shall we go?
Yes, let's go.
[They do not move.]

Written by: spiralx

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Yeah I've had this thought before. I think by modelling the poi body as four equal sections you'd be able to cover most cases - near the head for recoil wraps and airwraps, in the middle for hyperloops and thru wraps, and near the handle for, well, other stuff. It'd be computationally more complex for sure, but would allow for 99% of moves to be modelled.

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Efficient humour: "heh...wang "

Well, shall we go?
Yes, let's go.
[They do not move.]

POI THEO(R)IST

Love is the law.

Written by: NYC

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A basic equation for a flower would look like those old spirograph flowers that you'd draw by putting your pencil in one of those gear thingies.... Maybe that was just an American 80s thing.

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POI THEO(R)IST