why did my dforce rope BOOM ?

Hi everyone ,I has a problem in dforce rope , pls look the pics..
I have succeed in a few days ago in anther scene.
But this time , it boom..
what wrong did I do ?


01.png
1919 x 1032 - 65K


02.png
1918 x 1038 - 64K


03.png
1920 x 1030 - 110K


04.png
1909 x 1022 - 210K


05.png
1916 x 1029 - 195K
Comments
it goes normal at first few seconds ,but then it boom....
later, I think ,is it because I scale the rope to fit my two points'distance ?
so I go back to reset the scale of the rope ,then it goes right .
So....in simulation , we could not change the scale of the rope????
Go to the surfaces tab & turn off 'self-collide for all it's surfaces I think is most likely to fix the problem you had.
Do you get warnings about spring lengths being less than the offset value when the simulation starts?