Interpolation of transforms

[aqnuep]

Hi,

According to the manual, Bullet uses a fixed 60Hz internal update rate and if the simulation is not executed using an exact same step, it interpolates the result of the current and the previous simulation step results.

My question is how this interpolation happens? Does it mean that the transformation matrices of the current and the previous simulation step results are linearly interpolated or some other method is used?

I'm interested in this as I think a simple linear interpolation would be just a rough approximation. Think about a sphere moving on a parabolic path. If we interpolate the transformation matrices linearly then we would approximate this parabolic path using a line segment as between every step the movement would be interpolated like the sphere is moving to a constant direction with a constant speed.

Can anybody clarify the way how Bullet transformation interpolation works?

[aqnuep]

Can anybody answer the question, please?

Maybe I have to check it in the code but I suppose it wouldn't be that straightforward.

[Coderro]

It's probably linear, as at 60Hz linear interpolation will be good enough as long as you're visualizing the results in real time. If you visualize them with slow motion or use the data for some other purpose, just increase the frequency as needed, or use your own interpolation rather than Bullet's.