When I type -20 as the starting frame it jumps back to 0. I have enabled Allow Negative Frames and the problem persists. I’ve attached an example .blendExample.blend (478 KB)
Use negative frames is for the current frame, not start frame, to be able to scroll if some settings allow negative frames or preroll.
Reports on the tracker suggest that’s the intended behaviour and one can’t set a negative start frame.
https://developer.blender.org/T42151
https://developer.blender.org/T52872
I feel like I’ve done it before in order to get preroll for smoke and cloth… When I bake all active for my smoke it doesn’t cache the negative frames