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Different values are required to balance forces in the physics tab with the force of gravity. For example, if the force of gravity is defined as -9.8, a force field setting of about 234 is required to counter the effect of gravity for an object with a mass of 1.

My expectation was that the force-field setting of 9.8 should counter gravity. However, the required setting is far away from that. Changing units from None to Metric did not affect the ratio.

How is the force necessary to counter gravity calculated in Blender?

For example, create a simple scene with a cube, a plane, and an empty. Enable rigid-body dynamics for the cube. Enable a force-field for the empty on the physics tab.

Scene setup

The gravity is left at the default setting.

gravity default

By experimentation, the counter acting force-field is found to be about 234 to balance the cube.

force-field setting

This setup results in the cube staying almost still. It would be useful to be able to calculate the force-field setting required to calculate the balance force rather than use experimentation.

The blend file with this setup is located at:

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  • $\begingroup$ Is it true that you want the cube to be stationary at certain times and then to be acted on by gravity at other times? $\endgroup$
    – atomicbezierslinger
    Commented Nov 29, 2015 at 20:09
  • $\begingroup$ That is one use, but not the main reason this was asked. This question was prompted by blender.stackexchange.com/questions/23925/… , where force-fields are used to set up the rest position for a spring. The values don't make sense if force = mass * acceleration. Since the mass is 1, the acceleration (gravity) is -9.8, then there must be a scaling term or some other calculation is involved. $\endgroup$
    – Ed Tate
    Commented Nov 29, 2015 at 20:23
  • $\begingroup$ Blender forces and values have little in common with physics. Only the spatial values will be correct. Everything else are just some code coefficients, even the gravity accel (which just looks right). $\endgroup$
    – Jaroslav Jerryno Novotny
    Commented Nov 30, 2015 at 9:38

1 Answer 1

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The force field has many paremeter such has application point, shape of the object, range ... whereas the gravity is the global variable that has no parameter except it's the value. So you can't expect to counter the gravity with a forcefield at a value of 9.8 .

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