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Help  Rope around another rope - added partial solution
#1
Love the Ropes! makes great wire/cables
So I have a rope that is in a single loop (not touching) similar to a wrapping an extension cord, and at the apex (top where the 2 ends are close together) I made another rope around the apex, and I closed the loop ends to form a zip tie, again, this zip tie doesn't touch the cord (even checked the rendering from 0.8 to 1 to verify). but when I hit play, the cord bounces out of the zip tie loop, and the zip tie falls to the floor.

***EDIT and how I think I solved it... but is it correct?***
Zip tie blueprint-
thickness 0.03
Resolution 0.3 (the lowest I could make it... 0.25 "did" work, but if I moved anything it broke the zip tie)
pool particles 2

Zip Tie Distance constraint: stretching scale 0.2 (had to oversize the zip around the cord, then on runtime it shrinks)
Zip Tie Bending Constraints all zeroes (zip ties shouldn't bend)

Zip tie was anchored to a cube in the middle by the loop apex

Cord Blueprint:
thickness 0.1
Resolution 0.6 (the lowest I could make it... lower and it would fall through the zip tie)
pool particles 100 (default)
Cord Bending constraints all zeroes (emulating an electric cable that's stiff)

anchored the ends of the loop to cubes

Further Edit: if I unanchored the zip tie, the loop sides popped out of the zip tie, so I increased the stretching scale to 0.4 (Corrected), added High static friction and it "mostly" held in place, gravity pulled the loops ends mostly through the zip tie, but it still held a "small" loop

Enabled Surface collisions to reduce resolution and it really helped. now the cord acts like a heavy gauge power line.
Enabled Self collisions so the cord that looped, doesn't overlap itself, and instead rests besides itself.
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#2
(19-12-2023, 03:53 PM)burntends Wrote: Zip Tie Distance constraint: stretching scale 0.2 (had to oversize the zip around the cord, then on runtime it shrinks)
Zip Tie Bending Constraints all zeroes (zip ties shouldn't bend)

Try surface collisions. These bridge the gaps in between particles so that resolution isn't so important when it comes to collision detection, so you can get away with lower resolution ropes.

(19-12-2023, 03:53 PM)burntends Wrote: Further Edit: if I unanchored the zip tie, the loop sides popped out of the zip tie, so I increased the stretching scale to 4, added High static friction and it "mostly" held in place, gravity pulled the loops ends mostly through the zip tie, but it still held a "small" loop

A stretching scale of 4 will make the rope 4 times longer (400%) than its original length. Conversely, a value of 0.2 will make it 20% of its original length. These values sound a little bit too extreme to me, but I have a hard time picturing your use case in my head so I'm not entirely sure if there's a simpler solution.

If you could show some pictures of what you're trying to accomplish, I might be able to offer more accurate advice.

kind regards,
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#3
(20-12-2023, 08:14 AM)josemendez Wrote: Try surface collisions. These bridge the gaps in between particles so that resolution isn't so important when it comes to collision detection, so you can get away with lower resolution ropes.


A stretching scale of 4 will make the rope 4 times longer (400%) than its original length. Conversely, a value of 0.2 will make it 20% of its original length. These values sound a little bit too extreme to me, but I have a hard time picturing your use case in my head so I'm not entirely sure if there's a simpler solution.

If you could show some pictures of what you're trying to accomplish, I might be able to offer more accurate advice.

kind regards,
thnx, yes I had meant to add a new update to include the surface collisions (and self collision on the loop cord so that it didn't overlap itself) 
the stretching scale should have been 0.5 not 5, that was a typo (I will correct)
I also upped the dampening to 0.35 to reduce jittering which was initially high when the zip tie compressed itself around the cord.
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