Hair jumps off emitter after 1st frame of animation

Hi guys, I’m clearly not looking in the right places to work out what’s going on here, so would love your advice. I’ve been working through the CG Geek tutorial “Create a Beautiful Animated Creek” (links to youtube) with a plan to make an animation from the result.

The scene has 4 particle systems for the foliage which renders nicely for the first frame, but from the 2nd frame onwards the hair is scattered around the emitter, not just eminating from it. Here’s the 3Dview of the first 2 frames to illustrate what I mean:

I thought this might just be in the preview, but after rendering the 2nd frame showed much of the plants vanished from the camera view, it’s confirmed as a “feature” of my animation. The positions don’t change (at least in this solid view) between frames 2 and 300 - they go wrong on the 2nd frame and stay that way.

There are no animation keyframes on the emmiter, just the camera LocRot and focus point.

I’m really hoping there’s something obvious to those with more experience in these things. Where should I be looking to debug this?


I deleted the particle systems and started over, stepwise, to see where it goes wrong.
I can keep the plants growing where they should so long as I leave Hair Dynamics off.
I’ll press on and see if this is the solution. I’m still far from sure why this causes the symptom I’m seeing.

I’m still none the wiser as to why Hair Dynamics causes this, however turning it off was the answer in this case.