[1.9.8]Thin rope makes itself explode
9 posts • Page 1 of 1
[1.9.8]Thin rope makes itself explode
See below scene.
http://www.algodoo.com/algobox/details.php?id=56409
P.S.
I've reported this issue from bug-reporting function of Algodoo 1.9.8b.
But I couldn't confirm that it had really reached to developers...
http://www.algodoo.com/algobox/details.php?id=56409
P.S.
I've reported this issue from bug-reporting function of Algodoo 1.9.8b.
But I couldn't confirm that it had really reached to developers...
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mori-d - Posts: 28
- Joined: Sun May 02, 2010 1:56 am
Re: [1.9.8]Thin rope makes itself explode
I would say - all low density things makes itself explode with new solver
Dream of Algodoo as game development engine...
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Kilinich - [Best bug reporter 2010]
- Posts: 2098
- Joined: Mon Aug 31, 2009 8:27 pm
- Location: South Russia
Re: [1.9.8]Thin rope makes itself explode
You bug report did indeed come in, and I have answered you by mail (if the new system is working correctly...), but here's my answer so that everyone can see:
Large mass ratios (heavy object interacting with light object) is always a problem in simulations. Algodoo:s new direct solver does an incredible job on this, but it's still not perfect. In particular, stiff ropes still causes instabilities. Right now there isn't much to do about this other than making thicker ropes, heavier ropes, or making the rope softer.
This last options is probably the best one. To change the spring constant of new ropes, set Tools.ChainTool.springConstant to something lower than the default 1e6. For instance, a springConstant of 10000 will make a very stable rope for most situations, but will also make the rope more stretchy. It's a tradeoff.
Maybe the default rope spring constant should be even lower. I lowered it from 1e7 to 1e6 in 1.9.8, but maybe 1e5 or even 1e4 will do? With 1e4 a rope would stretch a meter when holding up 1000 kg.
Tell me what you guys think!
Large mass ratios (heavy object interacting with light object) is always a problem in simulations. Algodoo:s new direct solver does an incredible job on this, but it's still not perfect. In particular, stiff ropes still causes instabilities. Right now there isn't much to do about this other than making thicker ropes, heavier ropes, or making the rope softer.
This last options is probably the best one. To change the spring constant of new ropes, set Tools.ChainTool.springConstant to something lower than the default 1e6. For instance, a springConstant of 10000 will make a very stable rope for most situations, but will also make the rope more stretchy. It's a tradeoff.
Maybe the default rope spring constant should be even lower. I lowered it from 1e7 to 1e6 in 1.9.8, but maybe 1e5 or even 1e4 will do? With 1e4 a rope would stretch a meter when holding up 1000 kg.
Tell me what you guys think!
Emil Ernerfeldt, lead developer
- emilk
- Posts: 616
- Joined: Mon Aug 31, 2009 11:01 am
- Location: Umeå, Sweden
Re: [1.9.8]Thin rope makes itself explode
Add rope spring constant into interface and auto-adjust it depending on density (actually was suggested before) .
Dream of Algodoo as game development engine...
-
Kilinich - [Best bug reporter 2010]
- Posts: 2098
- Joined: Mon Aug 31, 2009 8:27 pm
- Location: South Russia
Re: [1.9.8]Thin rope makes itself explode
if you type in Tools.ChainTool.springConstant = 1e5, 1e4... it fixes the problem when you make a loop out of the rope
- motoxlife08
- Posts: 1
- Joined: Fri Nov 04, 2011 3:52 am
Re: [1.9.8]Thin rope makes itself explode
Any chain constant above 10^5 is considered "dangerous". Use with care. If your rope explodes, simply lower its strength.
Emil Ernerfeldt, lead developer
- emilk
- Posts: 616
- Joined: Mon Aug 31, 2009 11:01 am
- Location: Umeå, Sweden
Re: [1.9.8]Thin rope makes itself explode
When I need an ideal rope, that is one that doesn't push and just pull when stretched, and doesn't do anytning else (like bend around a wheel or advanced stuff that real ropes do) I make one in Thyme. It is a spring with a postEvent code that sets the spring constant and damping high when the spring is stretched, and low otherwise. To pull and slacken the rope I change its length in the onKey event.
- Kitesurfer
- Posts: 10
- Joined: Thu Jan 07, 2021 5:27 pm
Re: [1.9.8]Thin rope makes itself explode
Kitesurfer, this thread is almost 10 years old. Replying here wont contribute to any conversation anymore and is considered a massive necropost.
- FRA32
- Posts: 229
- Joined: Wed Dec 03, 2014 9:51 pm
Re: [1.9.8]Thin rope makes itself explode
Thank you for the guidance, FRA32.
As a newcomer on the site, I found some of the old posts very useful. Ropes explode, TotImp(3) shows force divided by sim.frequency, objects may be put inside geometries - this and others are insights you don't find in manuals or among the heaps of old help-me-with-this-and-that posts. I thought by pointing out the usefulness in a comment thus giving them a fresh timestamp would make it easier to find the really useful stuff.
But maybe there are better ways? And maybe there is a value in letting what's sleeping be left in peace?
As a newcomer on the site, I found some of the old posts very useful. Ropes explode, TotImp(3) shows force divided by sim.frequency, objects may be put inside geometries - this and others are insights you don't find in manuals or among the heaps of old help-me-with-this-and-that posts. I thought by pointing out the usefulness in a comment thus giving them a fresh timestamp would make it easier to find the really useful stuff.
But maybe there are better ways? And maybe there is a value in letting what's sleeping be left in peace?
- Kitesurfer
- Posts: 10
- Joined: Thu Jan 07, 2021 5:27 pm
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