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Can't set negative Frame start
Closed, InvalidPublic

Description

System Information
Linux 64 bit (mac, win)
Nvidia

Blender Version
Broken: 2.72
Worked: not sure

Short description of error
Wanted to set start frame to a negative number to view particles starting at frame -300. Allow Negative Frames is turned on. Can't set start frame below 0.

Exact steps for others to reproduce the error

  1. Start Blender
  2. Enable Allow Negative Frames i User Prefs
  3. Set start frame to -100
  4. Start frame can't go under 0

Event Timeline

Kasper Jansen (janz) raised the priority of this task from to 90.
Kasper Jansen (janz) updated the task description. (Show Details)
Kasper Jansen (janz) edited a custom field.
Bastien Montagne (mont29) changed the task status from Unknown Status to Invalid.Oct 8 2014, 7:05 PM
Bastien Montagne (mont29) claimed this task.

Thanks for the report, but no bug here, things work as intended in code (looks like some output format do not support negative start time…).

It may not be a bug, but i'm wondering what the point of "allow negative frames" is when you can't render them? I have a setup with paticles that start at frame -300 and and my shot starts at frame 1. All is well until i need to render the preroll from -300 to 0. I know that i could move all my animation in the scene and start my particles at frame 1 instead but this could be a very time consuming process (can you move a particle cache?). I understand that some output formats doesn't support negative frames but with frame sequences this is just a character in the frame numbers(I know that it probably goes deeper than than in the code). It may not be readable in blender or other packages but i usually just rename/renumber in external software as needed. I hope this all makes sense in some way. In any case it would be nice to hear if you have any suggestions as to how i would go about rendering the particles before frame 0.

It would be very helpful if at least the simulation did actually work in the negative time - you usually do not want to render the negative time anyway, but you just want things to get going in the simulation, and then render it from frame 0.

Still, this is quite a bad limitation :(

Please address this issue

Tried with 2.76

I'm running into this same issue in 2.81. I encountered it because for some unknown reason my clip loaded intro the video editor on negative frames. because of this feature I'm unable to track my footage

Beyond my specific problem, I agree with Vaclav Benc. it would be very helpful to have access to the negative frames for simulation.

It would be great to hear what the use of "Allow Negative Frames" is when you can't actually set anything below 0. I needed this atm and it seems there is no work around? 2.82 still not working. Why is it limited at 0 where the timeline clearly shows a negative range?

This comment was removed by Gad (gadas).