Maximum angular velocity

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fnevgeny
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Joined: Thu May 03, 2018 1:56 pm

Maximum angular velocity

Post by fnevgeny » Thu May 03, 2018 2:13 pm

Hello,

It seems there is a limit of the angular velocity, specifically, 100 rad/s. Using applyExternalTorque(), the angular velocity at first increases correctly but then is capped once 100 is reached. Alternatively, I can set a value directly with resetBaseVelocity - which at first glance works fine (getBaseVelocity returns the same vector), but de facto physics corresponds to 100 rad/s again, as is seen both in the visualization and actual interactions, e.g., of the rotating body with a surface.

I haven't found any mention of this in the docs - nor a way to raise this limit. Any pointers?

Thanks,
Evgeny

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Erwin Coumans
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Re: Maximum angular velocity

Post by Erwin Coumans » Thu May 03, 2018 2:52 pm

You can override the maximum angular velocity using btMultiBody::setMaxCoordinateVelocity

This maximum velocity is a safety mechanism, to avoid energies going to infinity.

What are you trying to achieve with a very high velocity?

fnevgeny
Posts: 2
Joined: Thu May 03, 2018 1:56 pm

Re: Maximum angular velocity

Post by fnevgeny » Thu May 03, 2018 3:21 pm

Thanks for the quick response!
Erwin Coumans wrote:
Thu May 03, 2018 2:52 pm
You can override the maximum angular velocity using btMultiBody::setMaxCoordinateVelocity
It seems there is no equivalent in the Python binding (I've just started playing with pybullet to have a quick idea whether the library would be useful to me; will switch to C soon).
What are you trying to achieve with a very high velocity?
To simulate the table tennis ball dynamics (want to understand from the first principles why I play so badly :)). 100/(2*pi) ~= 16 RPS is actually rather limiting for modelling of practically any ball-based game. Maybe a warning should be printed when the clamping occurs; I spent some time tinkering with ball spin until realized the unexpected ball dynamics is due to some artificial limit.

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