Follow path empty jumping in random frames

I’m stuck, tried many options none of them work. I have a spaceship parented to empty, empty is following path, in preview everything looks ok, but in render some frames are like the empty would speed up for one frame, and went back in place. Spaceship is rigged with armature and drivers mix, it also has particles hair on it. Tried fixed position checkbox and without it, tried nurbs path vs bezier, baking hair particles on ship, baking follow path animation, apply location and rotation on empty, issue still remains. It happend once in the past, but this was one frame so I just replaced it with duplicate of previous one as a workaround, so now I decided to test it first with quick workbench render, and it gives me about 20 of this bad frames out of 600. Where the issue might be? I’ts like empty couldn’t keep up for one frame randomly, and I don’t have any Ideas left. Camera also double checked. Only thing it seems to have impact would be number of particles, but not sure is it really connection or just lucky render.

Also not sure if this is normal empty on path behaviour, once I go frame back it changes position relative to the ship.

First think I would check would be for any dependency loops. Open a console window (main view menu) and look for any “dependency cycle” warnings.

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Thank you for an answer.
It seems you are right indeed, there is sth like that in mysterious console window, but as a not programmer just simple mortal here with like 5 months 3d total and 3 month blender specific exp I wonder what the heck is meaning of this symbols (-f, -a, 30 [this would be framerate?] 600? Ok so those should be render parameters) what is richtiffpicture ignored?

That stuff doesn’t matter, it’s about your rendering operation, not the dependency loop. The important thing is to see that you have a dependency loop where cockpit depends on engines via parenting, but engines depend on cockpit via some driver. Gotta decide what you want driving what.

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Wow, I remember that I tried to make it exactly opposite way, It seemed intuitively more in order but for some reason driver doesn’t worked at all (maby another dependency loop), I wanted to make engines moving depending on tilt of the cockpit(but also been able to control it independently), cockpit is holding rest of the ship as children, and empties for steering, and is a child of this biggest empty, now I know where to look at, thank you mister programmer, you definitely saved me from dental visit because I was eating my teeth on this like whole day. So reriging it is.

Holy f%@#@[email protected] it works, it finally works! Not a single bad frame confimed! I’mean plenty of bed keyframes, but only because I didn’t played with camera long enough!

Thank you!

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