# What's Mass, Force, and Torque measured in?

I’m making a racing game and the lack of concrete units is becoming a problem. I know that AngV is measured in Radians/sec and for the sake of argument, let’s say 1 blender unit = 1 meter (derived from the default gravity of 9.8 ), that would mean LinV is meters/sec.

My question now is what on earth is Mass, Force and Torque measured in? I thought at first Mass was in kg, but it can’t be- the maximum value (100) would be only 220lbs :-?

Is force measured in Newtons? Torque in Newton-Meters??

Thanks

as for the limits on mass, if everything relative to everything else is correct you should be able to get good results

and since changing the mass changes the effect of a force [if I recall correctly], applying the same changes from real values [say, dividing by 1000] to the forces should keep the changes

Yeaa, I kno that the relative masses are what really matter. I was just wondering if there’s any precedent, like how Blender units are generally considered to be meters? I’ve searched the forum but can’t seem to find any useful info on the topic. Thanks

What does the mass DO anyway?
I mean, how does it affect the dynamic actor?

Objects with higher mass take more force to get up to speed, and have greater momentum once they get going, they’re also more affected by friction. (Just like in real life, actually…)

Objects of higher mass are less susceptible to friction (once set in motion), according to my Physics lab test results. Higher surface areas are different, but you’re disregarding density I think.

friction is a function of force [and area] on the surface

so, it does increase with more mass, but I guess it is possible it would not increase as quickly as intertia.

[but I thought they were the same power, would increase at the same rate]

I believe it would be most correct to say that these variables apply in proportion to one another, rather than being linked to any absolute (e.g. Earthly) scale.

So, an object with a Gravity of 2.0 would experience twice the gravity (say) of one with 1.0, because the ratio between the two values is 2:1.

Much the same way that conflicting Constraints are evaluated against one another by the ratio of their Influence variables, not the absolute numerals involved.

I don’t think surface area is taken into account in Blender. The only effect mass has in Blender is how much force it takes to make something start moving. (It seems to slow down at the same speed regardless of the mass.)

Surface area is not taken into account - Blender uses the Couloumb friction model, where friction is directly proportional to the force between the two objects.

I’m kinda confused about blender’s “gravity.” The 9.8 setting of gravity, which is supposed to be about the gravity on earth (right?), definetly doesn’t make my objects fall as if they’re on earth. Even 25 gravity doesn’t do this, i have to apply a downwards force on all of my objects to get real seeming gravity.

Pooba

Pooba, try giving your objects more, (or less?) mass. Objects don’t act realisticly with the default mass of 1.

[EDIT] Oh yeah, check to make sure you didn’t increase the damping setting. With higher damping values, your object’s maximum falling speed will be too slow, even if you increase the gravity. If you’re using damping to keep your objects from going too fast, increase friction or decrease force instead.

Yea, I’m pretty sure it’s the damping. Mass (correctly) doesn’t change an object’s falling speed. On a related note, I noticed the maximum Mass value in the latest CVS is 10,000. Might be able to use kilograms after all