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+--- Thread: Mass appears to not work (/thread-494.html)
Mass appears to not work - secondplace - 04-28-2019
Mass settings in PhysX Shape operator crashes my max a lot. The Mass Operator is stable but it does not seem to do anything unless i set the mass to 0.
How to use this operator?
RE: Mass appears to not work - tyFlow - 04-28-2019
That's.....very odd. Could you attach a scene file or send to support@tyflow.com? I use PhysX shape mass and the mass operator often without issues, although maybe there's something I'm overlooking that would be revealed in your setup.
RE: Mass appears to not work - secondplace - 04-29-2019
We just found what we missed, In the Force Operator there is a Force Affect rollout. After enabling the Relative to mass it works now.
What i do not understand right now is why the particles are not falling at the same rate regardless of their mass.
I first thought the mass is density (kg/cm³) but it does not appear so since the higher the density the lighter the object and not heavier. This is somewhat confusing since it should be the other way round.
(for example in the tyFlow_balloons_001.max scene the mass is set to 0.15, i thought that is because helium has a density of 0.178 kg/cm³)
I'm confused about the Gravity as well. In the tyFlow Modifier the default gravity is set to -1.0 is this equivalent to 9.81 m/s²?
Sorry for the physics related questions, just trying to understand all the parameters.
RE: Mass appears to not work - tyFlow - 04-29-2019
All forces are in units per frame.
Mass values are purely multipliers for forces and/or particle relations. For example, if two particles are bound together and one particle has a mass of 1 and the other has a mass of 10, the first particle will have to exert 10x the force on the second in order to maintain equilibrium. Same goes for forces...if you set forces to be relative to mass, a particle with a mass of 10 will take 10x the force to move it as a particle with a mass of 1. If you enable "relative to mass" for any force, including gravity, resulting velocities will be affected.
Anyways, not sure how your latest post relates to the crashing you said you were experiencing earlier...you mentioned setting relative to mass solved the issue, but crashes should not be happening at all.....if you could send an example scene reproducing the crash to me I'd appreciate it
RE: Mass appears to not work - secondplace - 04-29-2019
Thanks a lot for the explanation. Now that i look at it as a multiplier the results make sense
Unfortunately i didn't save the scene. I briefly tried to reproduce the crashes this morning to send it to you but could not. It was probably due to an odd order of doing things that led up to it.
RE: Mass appears to not work - Andreas Jalsovec - 05-07-2019
(04-29-2019, 06:24 AM)tyFlow Wrote: All forces are in units per frame.
Mass values are purely multipliers for forces and/or particle relations. For example, if two particles are bound together and one particle has a mass of 1 and the other has a mass of 10, the first particle will have to exert 10x the force on the second in order to maintain equilibrium. Same goes for forces...if you set forces to be relative to mass, a particle with a mass of 10 will take 10x the force to move it as a particle with a mass of 1. If you enable "relative to mass" for any force, including gravity, resulting velocities will be affected.
Anyways, not sure how your latest post relates to the crashing you said you were experiencing earlier...you mentioned setting relative to mass solved the issue, but crashes should not be happening at all.....if you could send an example scene reproducing the crash to me I'd appreciate it
This is an interesting point - so changing the projects FPS settings in the time configuration has an impact on the simulation and should be defined at the beginning.