Same effect occurs in Newton demos sandbox when bodies are in contact with tree collision.
I recompiled demos sandbox with MAX_FPS set to 60.0f so that the effect is more visible. BTW, when I change solver model to interactive the moving stops (even if the auto-sleep state is off).
This is not really important to me, as I can always use interactive solver model, but exact solver is
I was confused by 'softness' too and copied following comments from forum, it may help you as well.
As far as i understand it is a value controlling how fast interpenetrating bodies seperate. It's not a physical value, but more a 'recover from illegal state' thing.
I guess there is indeed a bug related on convex - static mesh / exact solver that Julio should fix before you can offer the exact solver as an option.
//NewtonMaterialSetSurfaceThickness // Thickness is how cloase the collision will be, you can for example set a small sickness value and the shape will not touch. //NewtonMaterialSetContactSoftness // softness in hwo fast penetration will be resulved (by penaltry force proportinal to the penetration.)
/* softness and elasticity are very different things. one is a function of penetration distance and the other is function of relative impact velocity
elasticity is the coeficient of restitution according to the equation of impulse. eleaticity is proportional to the relative velocity of impact at a contact.
softness it there to resolve interpenetration only. Softness is the penetration coneficient that is use to convert teh interpenetration is disatnce to an inpulse veliocity to recove from penetration, the velocity is then added to the impact velocity.
in future versions of Newton softness will be eliminated all together. you can leave the softnes coficient to the default and only work with elaticity.
yes elasticity is what some people call restitution
softeness is a penalty acceleration that is added to the contact point if they penetrate. it is not propotional to the penetration, instead the penetration is use as a switch to decide if using the softhness or not,
In Newton this parameter is not visual, is is in fact translate to an impulsive force add to the contact point, and it is one of the reason collision can go bad if you set that value to anything too high. the parameter have not physical explanation other that recover bodies from penetation. so the physics of it are umpredicatble since I do not have any physcial/mathematical expresion to add it to the engine. like I said, set it to zero, the engine do recover from penetration graciously by separating the at a constant speed when they penetrate.