Dynamic Simulation Masses

[Wilsonator]

I have a question about the design consideration as follows:

Design consideration 7
Keep masses similar and not too light. When linking two shapes with a dynamically enabled joint or a dynamically enabled force sensor, make sure the two shape's masses are not too different (m1<10*m2 and m2<10*m1), otherwise the joint or force sensor might be very soft and wobbly and present large positional/orientational errors (this effect can however also be used as a natural damping sometimes). Additionally, very low mass shapes should be avoided since they won't be able to exert very large forces onto other shapes (even if propelled by high force actuators!).

Consider two Cases:
Case A:
100kg mass
>Joint
>>5kg mass

Case B:
50kg mass
>Force Sensor
>>50kg mass
>>>Joint
>>>>5kg mass

My question is, say we broke an original 100kg mass into two 50kg masses connected by a force sensor, would this produce a better behaviour for the simulation? Ie., would Case A perform more stably than Case B?

[coppelia]

Hello,

I am haven't tested this directly, but I would say yes. The large mass differences usually generate very large and small numbers in matrices that need to be solved. Small numbers will get lost in that process. But it will depend on the physics engine you use. Vortex has very good characteristics regarding this, Newton is not that bad either.

Cheers