Realistic Cable Simulation

[andreas-lugert]

Hey Guys!

I would like to lern the techniques about the creation of realistic cable simulations.
If i create a cable, with locators and dynamic influences everything is working great, but whats going on if i need
this cable on another position as on the current one. And what i have to do if there is a cable that is connected on a human body that should collide with it...so there are many many question about it.

Well i can create a cable but not the detailed properties. May by there is a tutorial or some plugins for Maya 2011.

Thank you, and have a nice day!

[joojaa]

I would like to lern the techniques about the creation of realistic cable simulations.

Well do you want a simulation because you need to simulate something by design, or to alleviate amount of work? Then secondarily how much effort are you up to putting into the simulation? And third have you ever worked with simulations before?*

See simulation is usually a 2 edged sword. It can be very hard to get the simulation right, on the other hand. But  at the same time you loose control over the end result. So you should consider and specify what exact task you want the simulation to target. For example making a 100% correct cable simulation is not necessarily easier to work with. I mean theres probably a reason why you dont go forth and film cable rope, you dont get much more realistic than that. Then again it dont really workj out with most other animations. For example making also noose behave with a simulation like the real deal would require you to know how to lasso.

So inevitabvly you want the simulation to conform to reality ONLY partially in most cases. Sometimes prefeer actually keying a lot of the animation because simulation often makes iterating the animation difficult even hard, So putting some border contraints to things is a must here.

May by there is a tutorial or some plugins for Maya 2011.

I think thats a bad question I dont think you can fit the entire topic into the scope of a tutorial youd be interested to read, id say a book is more like it to tackle the problem field. Since youd need to discuss rigging it as well as managing the entire animation process which must accommodate to the simulation in question.

But yes not hard necceserily. Ultimately my main concern is that you dont actually want a simulation at all in the need you just think you do. As keying a realistically behaving rope is not actually very hard. But more importantly its easier to work rest of your animation with a manually keyed thing. Or half simulate bake and then animate. But if your a veteran simulator then yes you probably know all this by now.

So before i can give you maningfull answer you need to actually describe the situation. (and no i qwant it to work like the real deal is not a good answer becuse then im afraid you need to get some Ph.D. level help, even then its insanely hard to simulate something 99.99% correctly whereas 70-85% is usually trivially easy )

• When i taught out factory simulation to engineers half of the time, they just tough simulate now that solves all our problems. But then they did something that sidestepped the entire need to simulate. Such as making a simulation fo a gant chart that results in gfant chart to check the validity of the chart. Doh circle defilition its prettu clear it ends up saying  valid, no extra info was provided. So before comitting to simulation its clear to see the target goal (what you want to measure / achieve) and the possible simplifications you can live with.

[andreas-lugert]

Thanks for your answer!

The case where i have the problem is that i have a robot and this robot has some cables on his ridge.
Whats interesting for me is the problem that the cables should move with the interaction of the robot, is he moving to the left the cable has to jiggle, is he moving faster so the cable should jiggle much more. Of course, everything depends on the direction and the speed on the robots movements.

I could not belive it that it is so diffucult to say: "The start point of the cable is there, the end point is here, the cable has this mass and this stiffness and the start point maybe the end point is moving as fast as they were keyed!"

Thanks again for your answer!

[joojaa]

Well you will find that indeeed everything in 3d is dificult as it dont really work like reality.

I could not belive it that it is so diffucult to say: "The start point of the cable is there, the end point is here,
the cable has this mass and this stiffness and the start point maybe the end point is moving as
fast as they were keyed!"

Aaah thats easy (ish, bit tricky though. Overcostrained deforming stuff is allways mathematically a bit hard to handle). However you will find that simulation does NOT exactly work the way keying does. See reality has a continious state, maya has not. In maya everything is defined as a function of one frame, nothing form previous frame is inherited prefeerably. Why? Well see mayas supposed to be able to reconstruct any frameon the fly, past or future because you work your way up and down the time all the time. THis gets hairy very fast, and if you do not understand the difference it also get very convoluted Extremely fast. One of the key problems is that theres no controll. And what you see on the screen is no longer what you get, you only get the right result whan you playback. You must esure you bake or cahce stuff right before you render and so on.

Ok this is vary different form actually having a full simulation the cable is constrained at all times, Theres 6 different ways to do this. This is simplest, but nby no means best.

create dynamic hair.
Select follice set point lock to dont attach!
Hide original curve.
select one endpoint of dynamic curve choose [Dynamics] Hair->Create Constraint->Transform Or stick (and transofrm)
repeat for other end

Use this to deform yoru geo,

Now This works pretty OK, but due to the way hair actually works it doenst actually do very accurate job but if you know how maya works that shouldnt be a issue. Jsut up your samples and accuracy.

that it is so diffucult to say

well no but sometimes the architecture has caveats. For example making a sphere that rolls like the real deal on a arbirtray surface with you keying it is  as english language easy. make this ball roll on surface along this. But doing so without loosing the feedback in maya is INSANELY hard. Why? Well simply it works againts the grain of what entire maya is built for.

Sure you can get the result no problem but nevertheless the problem is still supidifyingly complex

[andreas-lugert]

Hi!

I made the Cable now with the help of Hair.
Everything is working great, but there is a little problem at the start and and point of the cable. I dont want that the cable is moving at the start and and end, so theses areas should be static.

If i made a cloth animation i can choose "Paint Vertex Properties", so i can paint the areas which should be static black and the others white...how can i do that with hair. Maybe the screenshot helps you!

[joojaa]

Ahh yes go back to frame 1 see that the constraint may not exactly on the endpoint snap it back to the endpoint. Then chek that the stiffness values arent too rigid and then set the default state (rest and start position at frame 1) to the shape you have.