Physics Warp - How Does Time Step Work

[arkie87]

It is not that simple. Because your ship is made of many parts and joints, and you simulate by step (like any physic engine do). You cannot know ahead of time what joint force to apply, as the force will depend on the divergence between the part of the ship. To make thing worse, each joint force change the behavior of other joints. You typically have 2 way to simulate joins (and all composition of these on various translation and rotation axes to for rail-like joints for instance):

- solid joints, where the 2 bodies are simulated as one, and a computation is done to know if the joint broke (in which case the engine switch to simulate the 2 bodies independently).

- dynamic joints, where the various bodies are simulated as if no joint existed, THEN a joint resolution engine kicks and try to make the whole thing converge to some realistic solution using the joints.

The dynamic joints are way more complex to simulate (it is especially hard to ensure that the joint resolution step will converge to some solution in a reasonable amount of time) but is necessary to simulate anything that will experience deformations, as your ship does. This is also extremely sensitive to the simulation step, as the pieces will diverge more and more from a realistic simulation at each step, and the work to make everything converge is more important.

OK now here my speculation of what is happening:

When you warp, the game increase the simulation step. That mean the pieces of you craft diverge more before the joint resolution kicks in. The put your ship back together, it has to go to more extreme solution, bending your craft in the process.

Yes, Kasuha pointed this out. It is basically the result of using explicit time integration (forces are calculated based on displacements, velocities etc... of current time step) rather than implicit integration, where forces are recursively updated based on values at future time step. It is well-known that implicit integration schemes are more stable than explicit (in general).