catenary ropes. wires or chains
escrandall
Posts: 500
in The Commons
Has anyone done a catenary rope - eg - attach a rope, chain or flexible wire between two points and let gravity pull it to to its characteristic catenary shape? A script and a many segment rope (or whatever) should do it. All it should need is the rope lenght, xyz for the beginning and end tie downs adn the rope segment length.. 'just wondering if anyone has done it?
Daz 3D is part of 
Connect
DAZ Productions, Inc.
7533 S Center View Ct #4664
West Jordan, UT 84084
Licensing Agreement | Terms of Service | Privacy Policy | EULA
© 2025 Daz Productions Inc. All Rights Reserved.
Comments
I've done similar work in blender with its physics engine and then exported to Daz.
I'd really love it if Daz could work in a physics engine of its own in an upcoming release.
...I wish I could find catenary wires for streetcars, light rail trams, and high speed passenger trains.
Dynamic wiring has been on my wish list for a while (well,.. a year)
So many posibilities
On rope, specifically - I am not aware of a "rope" item in either Poser or DS that can do this. It can be done in Poser, of that I'm sure, using either the dynamics engine or bullet physics as well as a few other select scripts/freebies/etc for Poser. CORRECTION - There's an "EasyPose" rope item out there, somewhere. If Easypose can work in DS, then you can do this with it. But, it doesn't allow for length selection beyond its modeled links. One could hide individual link groups, I would assume.
There are several freebie python scripts for Poser that feature generation of catenary objects, mostly chains though. (ShareCG has a few, others can be found at Morphography, IIRC, and a few other script places.)
The old "Easypose" chains and the like can be used to create caternary chains. I think those work in DS too, IIRC? Parent either end to a fixed spot and set the caternary to 1000, IIRC, and you'll get a good drape that simulates how gravity would effect that length when anchored at those points.
There's a python script for Poser, sorry, that one can use to help pose rigged lines/chains, whether or not they have IK features. IIRC, it's called "Draw a cord" and features a telephone cord. One clicks on a small screen, draws the 2d shape of the cord and then executes it and poses the cord that way. Again, IIRC, it can also be used to pose the cord, or any similar rigged object, in three dimensions instead of only along one axis.
I realize this doesn't help DS users much, but there could be solutions associated with these sorts of things. (Easypose, etc?)
DS has dynamics, right? If so, I'd imagine creating a long, thin, tube and setting the material properties so the walls don't collapse on themselves too badly and setting the ring of faces on the extreme ends as static, anchored at the selected points, would work, somewhat. (I don't work with DS so sorry I can't be of much help, there.) As long as there wasn't too much stretching, it might be convincing enough.
One issue confronting both platforms is the dynamic nature of draping and identifying collision objects as well as anchor points and, finally, the nature of the material/chain/line being draped. I would absolutely LOVE a dynamic wire/line/cord/chain/anything that would drape naturally across multiple objects while considering user-selected anchor points. This can be done in Poser and, I assume, maybe in DS too. But, at least in Poser, it's a non-trivial thing to get perfect, even with sciprting, dyanmics engine and bullet-physics. If I knew the bullet-physics engine well enough, it might be a lot easier than I think. :(
...Daz dynamics is a closed system proprietary to Optitex created clothingcontent. There are other third party tools available to do cloth dynamics. but not sure about soft body physics which is what sounds like is needed.
Personally I wouldn't want to deal with posing a prop by hand that has say a hundred (or more) segments that didn't have both an "easy pose" function and collision detection.
Easypose items do work in DS, I have an easypose tube, some chains, tentacles, heavy cable, etc. Some of them have morph options built in to do a few basic curves and waves, which is super-awesome. However beyond that, yes, you have to manually pose each and every numerous segment, which has discouraged me from using them. It would be exceedingly difficult to get them to go from point A to point B across multiple obsticles with realistic curvature in the middle of each, although a simple curve between the two end points isn't hard with the built-in morphs (see screenshot), although I don't think that's exactly the curve you are looking for. A product that is nothing more than a large number of pose sets for thse products would even be handy, although of course if one could script it that would be even better (except that I'm stuck with scripts that work in 4.8, but better for everybody else anyway.)
Urban Sprawl 2 also has some fixed (not poseable) cabling that might be useful under certain situations:
I've been wanting to find the time to learn Daz scripting but that's been real hard to do.
I don't think it would be too difficult to create a script that counts the number of segments and their length, then calculates the bends to get from point A to floor, then from floor to pont B.
I was thinking a null the user could place where they wanted the item to start and stop, and one where they wanted the lowest point. If there were extra segments then perhaps the script could start a circular pattern at the low point (as if a cord wound up on the floor) to use up the extra segments in the middle. There could also just be a simple droop option where you choose pont A and point B and it calculates the bends, if it hits the floor, then it lays flat until it starts to curve back up to point B.
In my mind it doesn't sound too difficult, but like I said, I need to actually learn the scripting first.
This is exactly what is commonly known as IK (inverse kinematics): calculate the bends based on the endpoints.
Great idea! When you are finished, post it in the Studio Scripts section; i am sure a lot of people (me included) could use it.
I seem to recall mjc writing a 'track creation' script for DS a while back - please forgive me if my memory is playing up on this. It created, I think, geometry on the fly, so I suspect with knowinghow to do that and taking two fixed points it could be possible to do 'dynamically' (though statically), but it would likely not be able to cater for nay intermediary items that might get in the way.
Or, if you could fix/lock the end points there is the VWD cloth and hair simulator available at 'rosity, which might be able to 'make dymanic' a suitable prop?
I thought about just converting to dynamics (I have the Dyn-creator) Problem being is tubes would probably tend to flatten out as they draped and links in a chain would probably fall through eachother since you can't have an item collide with itself. At least that's my guess.
I have the paid-for Optitex, and there definitely is an option for self-collision. Can't remember if it's in the free version, but you should check out the last tab for self-collision. VWD has self-collision and a free chain for you to test out. You usually have to make sure you have high enough mesh resolution for things like chains to work.
Did a quick test with 'air hose' (which I could mostly pose into something about right) and then used (most recently talked about dynamic thing I'm not going to refer to by name).
Decent result, and, with appropriate settings, didn't collapse.
I have neither the opttex plugin nor the vwd yet :( I'm very limited on what dynamics I can do right now
I created a long thin cyclindar (20 feet long, half inch diameter) and applied a d-former to it. Pulled it down, it gave a not-so smooth curve but expanded the field in the x-direction made it more like a true catenary. Not mathematically accurate I assume but it's free and easy to make, so there's that.