twisted pair cable pls help
 

Hi guys,

i'd like to model a complex cable, with 6 pairs of twisted threads in it. The trick is, the pairs are also twisted around each other (UTP like). Any idea how to approach this problem?
I'd highly appreciate any help.

this is actually very very easy to do.
though figuring it out might have been a bit of a challenge I will do my best to describe what needs to be done.
The only thing that varies between using poly cylinders and using nurbs cylinders is how things are named.
If you want polys you need to make a cylinder, and subdivions to the height for the twist to work properly, if you use nurbs you add spans to the cylinder.

On to execution:
Create a cylinder at co-ordinates 0, 0, 0.
Provided you are using defaults the scale should be 1's around and the cylinder should take up 4 boxes on the grid. Change the scale of the cylinder in the y axis to 20. Change the subdivisons for height or the spans(nurbs) to 20.
Duplicate this cylinder and translate it 2 on the x axis. Select both cylinders, duplicate and translate -2 in the z. You should now have 4 cylinders equally spaced in a square-ish format.
Go into the animation module. Select all 4 cylinders and then go to Create Deformers -- Non Linear -- Twist.
Then all you have to do is edit the end angle and you have 4 twisted wires.
If you are interested in things like phone wire which have twisted pairs the idea is the same. I would recommend the use of nurbs but use 2 cylinders side by side. Apply the twist to them. Delete history and duplicate them so that they are side by side. Then apply a twist to them and you should have 2 pairs of twisted wires nicely twisted around each other.

I hope that helps, Let me know!

-Cheers
-Alexander

Alexander, many thanks. It is almost exactly what i'm looking for. Strange that i didn't check this deformer before, i've been there.
The only challange that remains is twisting the bunch of cables that are already twisted. This is what i did:
- twist a pair of cables
- duplicate 3 times (resulting 4 twisted pairs)
- group all 4 pairs and apply another twist on them
It still works but some unwanted deformation occurs, i suppose as a result of those convoluted twists. I also tried this with history deleted but the object gets distorted all the same.
So this method basically works but i still need to twist all 4 pairs around each other.
Again, thanks for your help.

Out of interest whay are you making a 6pr UTP? Just I worked in telecomms for a few years on the cable side!

Yeah something like that. Although i'm no cable expert.

are you using poly's or nurbs?
have you tried increasing the poly divisions, or the number of spans in the original cylinders and doing it again?
I'll have a look and see if I can't figure it out and get back to you.

the only way i could avoid the deformation you mentioned was to take my twisted pairs - I could not get it to work with 3 pairs as it is a rectangular shape but 2 pairs was fine - and create a lattice deformer on them. Because the lattice acts as the outerbound if you apply a twist deformer to the lattice then you seem to get proper twisting.

I hope that helps a little better, as for 3 pair well you're going to have to get creative on that one haha.

-Cheers
-Alexander

Thanks for your effort to help me out:) I'm just done for today, i need to go grab some sleep.
I used a poly cylinder with 100 subdivisions, it must be enough. I'll try the lattice thing tomorrow.

To be honest i'd be happier with a nurbs circle extruded along a path but it requires some scripting because maya obviously can't do this job by default. And i'm not much of a MEL dude.

This is going to be sort of a cross section so to make it more exciting both the plastic insulation and the copper thread in it must be visible. Which means they must be separate objects.

well when you come up with a solution share it with us. and let us see some of the work too, sounds interesting I must say.

-Cheers
-Alexander

If you were after a commerical product then wire would be the choice:
http://cms.ticket01.com/index.php/wire
check out the tutorials - they are nifty.
Only minus is that it costs 60 euros.
There is an evaluation version so if this is not for a commerical project you should be able to make use of it (dont know if it is restricted in any way though)
Simon

Thanks, i know this plugin, i've got the demo. It does what i need but once the twisted pairs generated there's no way to twist them around each other. There's a demo picture on their gallery that's very similar to what i'm looking for, a gallows rope, but i suspect the inner threads are pure texture not geometry.

Plus the thing i said earlier, insulation and inner copper thread must not be the same object, i need to texture them separately. Tricky stuff.

I must say that plugin looks great, though i have no real use for it myself.. not now anyways.

As per the original issue, I have yet to find a proper solution.

is this what your after as far as your cables? the reason you are getting that "additional" deformation (a say this because you are actually getting the same deformation on the first twist it's just not as noticable) anyways is because the poly or nurbs or w/e pipe is facing at an upward angle, as you twist it you are getting the same effect as if you were to set it to 1 span in height and grab and drag the top vert in one direction. the pipes circumference isn't facing in the angle you want the pipe to flow in. i am trying to figure out the formula to determine the amount of stretch the pipe needs b4 the twist is applied dependent upon the height, number of twists and diameter of the pipe, however i am not as familiar with trig as i once was. also i am trying to figure out the interleave of the wire sets if any so they sit snug to each other interlaced so to speak. i'll let you know if i figure it out, it's really kinda a fun problem.

http://i167.photobucket.com/albums/u...mur/wires2.jpg

http://i167.photobucket.com/albums/u...mur/wires1.jpg

the wire plugin from the post above is exactly what you're looking for. the inner wires in the image you spoke of aren't
textures they are geometry, you just have to think non-linear. make a curve, make into wire w/o adding a profile, make as 3 wires, then make each of those three a wire again as 2 wires, the sets of 2 will wrap around each other and all 3 sets will wrap aswell, now it's just the matter that the demo is pretty limited. have fun. post some pics when you're done

http://i167.photobucket.com/albums/u...ur/12wires.jpg

OK so i did it my way, no fancy plugins or scripting :) The idea is actually not mine, someone helped me out. I just refined it a bit. So this is how it works:
- draw a nurbs circle & a path, extrude circle along path with rotation added, 2000 or so
- duplicate curves (surface can be dumped)
- extrude a smaller circle profile along duplicated curves, also with some rotation
- repeat previous steps with smaller tube, now extruding final geo
when i was done with a twisted pair i simply grouped them and duplicated 3x, with rotation 90 deg.

This may sound like a tedious workflow but in fact it's not that bad. Plugin images look gorgeous too but i just couldn't make the plugin work in a reasonable time so i thoguth i better do it manually. But i'll take another look at the plugin. Bunch of thanks to you guys.