Progressive weakening bug?

[betamax]

When simulating cloth - Using any value >1 in 'Progressive weakening' seems to only allow one cloth tear to be processed.
This doesn't seem like expected behaviour, though not sure.

[tyFlow]

Hard to tell without seeing your file, but a large progressive weakening value like 1.5 means most binds in a localized area will tear very quickly. What's likely happening here is that you're exceeding the max tears per frame threshold each frame, just due to the sheer number of binds tearing in that localized area because of the high progressively weakening value....so by the time the other binds are processed, they are not allowed to tear due to that max tear limit.

You probably don't want a progressive weakening value that high...but to see immediately results, before tweaking your progressive weakening settings, just increase the max tear thresholds.

Progressive weakening just means that for any given edge that tears, the surrounding edges will have their tear threshold divided by the specified amount. So a value of less than 1 means that all surrounding edges will become stronger...and a value greater than 1 means all surrounding edges will get weaker. A value of 1.5 is very high...any time a tear occurs, all surrounding edges will be 1.5x weaker. So as soon as a single tear occurs...the whole localized area will quickly disintegrate as the progressive weakening is multiplicative for each tear.

[betamax]

Hard to tell without seeing your file, but a large progressive weakening value like 1.5 means most binds in a localized area will tear very quickly. What's likely happening here is that you're exceeding the max tears per frame threshold each frame, just due to the sheer number of binds tearing in that localized area because of the high progressively weakening value....so by the time the other binds are processed, they are not allowed to tear due to that max tear limit.

You probably don't want a progressive weakening value that high...but to see immediately results, before tweaking your progressive weakening settings, just increase the max tear thresholds.

Progressive weakening just means that for any given edge that tears, the surrounding edges will have their tear threshold divided by the specified amount. So a value of less than 1 means that all surrounding edges will become stronger...and a value greater than 1 means all surrounding edges will get weaker. A value of 1.5 is very high...any time a tear occurs, all surrounding edges will be 1.5x weaker. So as soon as a single tear occurs...the whole localized area will quickly disintegrate as  the progressive weakening is multiplicative for each tear.

Thanks as always Tyson, that's really good to know. I tried upping the 'max frames per step' as you suggested, (as well as lowering prog. weakening) and even with value of 50,000, I'm still seeing similar behaviour. Sorry if this isn't what you meant. I've attached the zip file for you anyhow.

[tyFlow]

In your scene, since the cloth surface is fairly large, you need to increase the tear distance limit as well.

This limit controls the maximum combined length of edges that may tear per step. Right now it's also limiting the number of tears that may occur, due to the size of your cloth.

[betamax]

Great thanks again, will give this a try today.