Particles at start position when render, sometimes. Why?

[Splododyne]

I have particles emitted in boid mode and a force field with negative strength. The particles move around as boids and are contained by the force field. That works. Sometimes it looks fine on the Layout tab but renders with the particles at the start position. This is unpredictable. Rarely an attempt to render actually moves the particles to the start position. I’m baffled.

Any advice about what causes this?

Blender 3.6

Layout Tab

.
Render Tab

The images were done with 1000 particles. The blend file has 100 to make it small for upload.

Particles_Glow_Dance_EXP.blend (974.1 KB)

[joseph (J)]

You need to bake your particles

[Splododyne]

Thanks! That fixed it.