Forums > Beginner Poi Moves > The maths of the 3 Beat weave
Login/Join to ParticipateBRONZE Member
Member
28 posts
Location: Southampton, United Kingdom
Member
28 posts
Location: Southampton, United Kingdom
Posted:
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 
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 "
DIAMOND Member
The Ministry of Manipulation
2,523 posts
Location: Bristol, United Kingdom
The Ministry of Manipulation
2,523 posts
Location: Bristol, United Kingdom
Posted:
And yes, Matt those were the points I modelled
and it works
And yes, Matt those were the points I modelled
and it works
GOLD Member
old hand
920 posts
Location: New Zealand
old hand
920 posts
Location: New Zealand
Posted:
"and the beat counter reads 6
perfect "
yep
It's not quite right if you do in time because the the beats still count
1,2,3,4,5,6
instead of
_,2,_,4,_,6
The In time split time button works fine in 1 plane but when you switch to anothr plane it is reversed. I think this is because the cos and sin for the rotation are contolling the wrong axes, i'll check it out.
I'll code the poi body to be 5 conected points.
oooOOOO, i'm getting excited about the possibilities.
m
"and the beat counter reads 6
perfect "
yep
It's not quite right if you do in time because the the beats still count
1,2,3,4,5,6
instead of
_,2,_,4,_,6
The In time split time button works fine in 1 plane but when you switch to anothr plane it is reversed. I think this is because the cos and sin for the rotation are contolling the wrong axes, i'll check it out.
I'll code the poi body to be 5 conected points.
oooOOOO, i'm getting excited about the possibilities.
m
Spherculism ~:~ The Act of becoming Spherculish.
GOLD Member
old hand
920 posts
Location: New Zealand
old hand
920 posts
Location: New Zealand
Posted:
poibot v0.6
poibot v0.6
Spherculism ~:~ The Act of becoming Spherculish.
DIAMOND Member
The Ministry of Manipulation
2,523 posts
Location: Bristol, United Kingdom
The Ministry of Manipulation
2,523 posts
Location: Bristol, United Kingdom
Posted:
oh, I made it hit itself in the nads
oh, I made it hit itself in the nads
GOLD Member
old hand
920 posts
Location: New Zealand
old hand
920 posts
Location: New Zealand
Posted:
haha, thats impossible ~ poibot's way too much fun to watch spin, she must be female...
haha, thats impossible ~ poibot's way too much fun to watch spin, she must be female...
Spherculism ~:~ The Act of becoming Spherculish.
BRONZE Member
Still wiggling
5,967 posts
Location: Belfast, Northern Ireland (UK)
Still wiggling
5,967 posts
Location: Belfast, Northern Ireland (UK)
Posted:
well done lads.
well done lads.
Getting to the other side 
BRONZE Member
Member
28 posts
Location: Southampton, United Kingdom
Member
28 posts
Location: Southampton, United Kingdom
Posted:
Holy crap this has come along...i really need to check poi every second instead of every week
ok ok...dude that wanted the source code...err...you dont want the source code. I promise you....its a terrible uncommented crime against humanity ....but i'll make it available if you're interested
poibot....is...amazing....so close to exactly what i wanted to be done at the beggining of this thread ...
Holy crap this has come along...i really need to check poi every second instead of every week
ok ok...dude that wanted the source code...err...you dont want the source code
. I promise you....its a terrible uncommented crime against humanity ....but i'll make it available if you're interested poibot....is...amazing
....so close to exactly what i wanted to be done at the beggining of this thread ... Efficient humour: "heh...wang "
NYC
9,232 posts
Location: NYC, NY, USA
9,232 posts
Location: NYC, NY, USA
Posted:
The freestyle mode is amazing.
The only glitch seems to be at the end of every 'bar' of maxbeats... when he returns to the beginning, he does a little spaz glitch.
I'm finding new transitions just watching him. He did a nice transition from an offset hug to an isolated buzzsaw that I'm totally stealing.
The freestyle mode is amazing.
The only glitch seems to be at the end of every 'bar' of maxbeats... when he returns to the beginning, he does a little spaz glitch.
I'm finding new transitions just watching him. He did a nice transition from an offset hug to an isolated buzzsaw that I'm totally stealing.
Well, shall we go?
Yes, let's go.
[They do not move.]
GOLD Member
old hand
920 posts
Location: New Zealand
old hand
920 posts
Location: New Zealand
Posted:
Yeah that glitch is a bitch. It never used to be there, then it appeared, then i thought i got rid of it and now it's back.
I think i know how to get rid of it. It happens because for a split second the beat value is 1 more than maxBeat.
Been watching some awsome isolated butterfly patterns.
When she spins a random pattern over and over it makes the way we define 'moves' seem so arbitery.
m
Yeah that glitch is a bitch. It never used to be there, then it appeared, then i thought i got rid of it and now it's back.
I think i know how to get rid of it. It happens because for a split second the beat value is 1 more than maxBeat.
Been watching some awsome isolated butterfly patterns.
When she spins a random pattern over and over it makes the way we define 'moves' seem so arbitery.
m
Spherculism ~:~ The Act of becoming Spherculish.
BRONZE Member
Still wiggling
5,967 posts
Location: Belfast, Northern Ireland (UK)
Still wiggling
5,967 posts
Location: Belfast, Northern Ireland (UK)
Posted:
Whatcha gonna call her? I'm sure you can come up with something other than Poibot
Whatcha gonna call her? I'm sure you can come up with something other than Poibot
Getting to the other side
GOLD Member
old hand
920 posts
Location: New Zealand
old hand
920 posts
Location: New Zealand
Posted:
it's always been poibot i'm afraid, been well over a year in the making,
but i'm up for suggestions.
it's always been poibot i'm afraid, been well over a year in the making,
but i'm up for suggestions.
Spherculism ~:~ The Act of becoming Spherculish.
BRONZE Member
Still wiggling
5,967 posts
Location: Belfast, Northern Ireland (UK)
Still wiggling
5,967 posts
Location: Belfast, Northern Ireland (UK)
Posted:
Lol, ok then. Tis not very feminine though
Lol, ok then. Tis not very feminine though
Getting to the other side
NYC
9,232 posts
Location: NYC, NY, USA
9,232 posts
Location: NYC, NY, USA
Posted:
Split time butterflies in the wheel plane appear to be "In time"... though I'd happily admit I was wrong.
If I was doing butterfly buzzsaw and they both hit the bottom at the exact same time, I'd call that 'in time'. If my buzzsaw butterflies hit the front and back at the same time, I'd call that 'split time'.
Poibot disagrees with me.
Am I wrong? I think I might be wrong.
Split time butterflies in the wheel plane appear to be "In time"... though I'd happily admit I was wrong.
If I was doing butterfly buzzsaw and they both hit the bottom at the exact same time, I'd call that 'in time'. If my buzzsaw butterflies hit the front and back at the same time, I'd call that 'split time'.
Poibot disagrees with me.
Am I wrong? I think I might be wrong.
Well, shall we go?
Yes, let's go.
[They do not move.]
Carpal \'Tunnel
3,638 posts
Location: Brum / Dorset / Fairy Land
3,638 posts
Location: Brum / Dorset / Fairy Land
Posted:
you have no idea how much reading this has made me smile
thanks beautiful geeky people
you have no idea how much reading this has made me smile
thanks beautiful geeky people
Geologists do it in the dirt................ 
BRONZE Member
Member
28 posts
Location: Southampton, United Kingdom
Member
28 posts
Location: Southampton, United Kingdom
Posted:
Ok dude this thing is amazing, but you clearly have the X, Y and Z pos of every bit of poi so why not move it into 3D!
I was sure flash had a 3D engine (if not built in then as a library)
Swift 3D seems to be flash's 3D animation suite
https://www.erain.com/products/
But yeh, at least when i was whacking it together in OpenGL the hardest bit was working out the positions on the X,Y and Z and just rendering the correct polygons( or models 3D poi model ). Seeing as you have the X,Y and Z it seems the hard bit is over and all you need to do is render a nice 3D poi in the appropriate positions!
It must be done....especially with your current isometric 3D studio max style display which is BEGGING for that 4th window to be the 3D view
EDITED_BY: sinjax (1105090975)
Ok dude this thing is amazing, but you clearly have the X, Y and Z pos of every bit of poi so why not move it into 3D!
I was sure flash had a 3D engine (if not built in then as a library)
Swift 3D seems to be flash's 3D animation suite
https://www.erain.com/products/
But yeh, at least when i was whacking it together in OpenGL the hardest bit was working out the positions on the X,Y and Z and just rendering the correct polygons( or models 3D poi model ). Seeing as you have the X,Y and Z it seems the hard bit is over and all you need to do is render a nice 3D poi in the appropriate positions!
It must be done
....especially with your current isometric 3D studio max style display which is BEGGING for that 4th window to be the 3D view EDITED_BY: sinjax (1105090975)
Efficient humour: "heh...wang "
newbie
16 posts
Location: united kingdom
16 posts
Location: united kingdom
Posted:
hello just read this and i would like to say i am realy realy confused cos i hate maths lmao
thanks
hello just read this and i would like to say i am realy realy confused cos i hate maths lmao
thanks
---------------------
i am hard but i'm soft, i am fruity but i'm sweet, i am jelly,what am i?
GOLD Member
old hand
920 posts
Location: New Zealand
old hand
920 posts
Location: New Zealand
Posted:
The in time split time thing seems to vary according to the plane, i think i have sin and cos round the wrong way for the localX and localY values in the wall plane. And you're right, if you're doing butterfly In time, then they cross top and bottom, if you do split time they cross left right.
The 3 views are indeed begging for a 4th in perspective. Glass sent me the equations i need to do it in flash. However as musashii pointed out on sph'ism, shockwave has uilt in 3d engine which is far better to use. I downloaded a trial copy of director today and it seems as easy to use as flash, gonna do a 3d tutorial and see how possible it is to rewrite the whole thing in shockwave. Cos at the moment the localZ value (going in and out of your monitor) is a bit of a bodge because in flash ou cannot have 2 movieClips on the same _level, that's why if both poi are at the same depth the green one disappears (beause it draws the green one at a certain level and then draws the red one on the same level, which deletes the first.
If i do it in shockwave i can reder a fully boned model spinning in 3d with a moving camera and particle effect, like ribbons or fire.
I don't think swift is all that, but i could be wrong.
Thanks for all the feedback guys,
m
The in time split time thing seems to vary according to the plane, i think i have sin and cos round the wrong way for the localX and localY values in the wall plane. And you're right, if you're doing butterfly In time, then they cross top and bottom, if you do split time they cross left right.
The 3 views are indeed begging for a 4th in perspective. Glass sent me the equations i need to do it in flash. However as musashii pointed out on sph'ism, shockwave has uilt in 3d engine which is far better to use. I downloaded a trial copy of director today and it seems as easy to use as flash, gonna do a 3d tutorial and see how possible it is to rewrite the whole thing in shockwave. Cos at the moment the localZ value (going in and out of your monitor) is a bit of a bodge because in flash ou cannot have 2 movieClips on the same _level, that's why if both poi are at the same depth the green one disappears (beause it draws the green one at a certain level and then draws the red one on the same level, which deletes the first.
If i do it in shockwave i can reder a fully boned model spinning in 3d with a moving camera and particle effect, like ribbons or fire.
I don't think swift is all that, but i could be wrong.
Thanks for all the feedback guys,
m
Spherculism ~:~ The Act of becoming Spherculish.
addict
666 posts
Location: Netherlands
666 posts
Location: Netherlands
Posted:
DAMN matt, thats brilliant. Wow!
Hey if you press randomize all, it even looks like matt doing his crazy butterfly/isolation/threading combos
Once again, wow, fair play.
DAMN matt, thats brilliant. Wow!
Hey if you press randomize all, it even looks like matt doing his crazy butterfly/isolation/threading combos
Once again, wow, fair play.
Come forth and thou shalt win enternal happiness. but he came fifth so he won an electric toatser.
BRONZE Member
Member
28 posts
Location: Southampton, United Kingdom
Member
28 posts
Location: Southampton, United Kingdom
Posted:
welp, good luck with the flash 3D stuff. By the ways, how open source is your stuff? After my exams are over and i have some time to breath id definetly like to have a go at porting it to C++ and openGL from flash?
welp, good luck with the flash 3D stuff. By the ways, how open source is your stuff? After my exams are over and i have some time to breath id definetly like to have a go at porting it to C++ and openGL from flash?
Efficient humour: "heh...wang "
GOLD Member
old hand
920 posts
Location: New Zealand
old hand
920 posts
Location: New Zealand
Posted:
Cheers MOT, that's just the beggining I wish i could spin poi that well, and I wish my poi would pass straight through my body and I wish I could do perfect head isolations but hey. Very addictive to watch tho.
sinjax, once I've tidied up the code it will be available to anyone who wants it. At the moment it is quite a mess. I need to go through it and turn everything into functions, instead of just copy and pasting it all.
m
Cheers MOT, that's just the beggining
I wish i could spin poi that well, and I wish my poi would pass straight through my body and I wish I could do perfect head isolations but hey. Very addictive to watch tho.sinjax, once I've tidied up the code it will be available to anyone who wants it. At the moment it is quite a mess. I need to go through it and turn everything into functions, instead of just copy and pasting it all.
m
Spherculism ~:~ The Act of becoming Spherculish.
The Ladiees Man
360 posts
Location: near swindon/ oxford
360 posts
Location: near swindon/ oxford
Posted:
good stuff, thats wicked!
good stuff, thats wicked!
I'm going to leave the army and run away to the circus
if not i will just become a MI5 agent !!!
SILVER Member
lurker
380 posts
Location: Nashville, TN, USA
lurker
380 posts
Location: Nashville, TN, USA
Posted:
>>When she spins a random pattern over and over it makes the way we define 'moves' seem so arbitery.
that's prolly because we have something called 'collision detection' in our world. we can't spin arbitrary patterns in space -- our own arms and chains (and often faces and nads and other things) get in the way. the other reason I don't know if that type will ever work is because one of the instruments you have to model perfectly is the human body. generating all the possible combinations of angles we can put our body into is equivalent to listing all possible poi angles about that body. the poi are the easy part, and can obviously be simulated (gets harder with tangles, i guess)-- the bodies, though, are near impossible to code more fully than a flexible person could try in real space easier. if it gives us even a few newideas, it's got to be worth it though, right? and it can easily show newbies certain specifics they'd not gotten in their head. I'd concentrate on getting the wrists and elbows to start looking a little more realistic, next. beautiful job coming up with an interface that works so well, too!
-- dut
>>When she spins a random pattern over and over it makes the way we define 'moves' seem so arbitery.
that's prolly because we have something called 'collision detection' in our world.
we can't spin arbitrary patterns in space -- our own arms and chains (and often faces and nads and other things) get in the way. the other reason I don't know if that type will ever work is because one of the instruments you have to model perfectly is the human body. generating all the possible combinations of angles we can put our body into is equivalent to listing all possible poi angles about that body. the poi are the easy part, and can obviously be simulated (gets harder with tangles, i guess)-- the bodies, though, are near impossible to code more fully than a flexible person could try in real space easier. if it gives us even a few newideas, it's got to be worth it though, right? and it can easily show newbies certain specifics they'd not gotten in their head. I'd concentrate on getting the wrists and elbows to start looking a little more realistic, next. beautiful job coming up with an interface that works so well, too!-- dut
SILVER Member
newbie
16 posts
Location: Thanet, United Kingdom
newbie
16 posts
Location: Thanet, United Kingdom
Posted:
well ive just read the first post, not gonna read through all the pages, i do 3d animation and i think your crazy! if you wanted to animate it surely it would be easyer to just have the poi follow a path, that way its easyer to edit and put it natural imperfections to the animation
Kenetor
well ive just read the first post, not gonna read through all the pages, i do 3d animation and i think your crazy! if you wanted to animate it surely it would be easyer to just have the poi follow a path, that way its easyer to edit and put it natural imperfections to the animation
Kenetor
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