Problem summary
When rotoscoping a scene, If a user uses a FrameHold, Transform & multiply before a merge in a rotoscope, it can break the background renderer.
It will either stop and nothing will be rendered, or there will be major graphical glitches in the output files.
This also happens with Nuke11's Frame Server.
Customer reported version
nuke.10.5v1
Customer reported platform
n_a_linux
Steps to reproduce
1) Open the Nuke file attached to this report.
2) Replace the Read node with your own image sequence.
3) Use the 'Background Render (Frame Server)' render option when rendering.
Result) The background error will either error and stop OR finish and display a glitchy output file.
Workaround
Option 1:
1) Copy the animation from the Multiply Node.
2) Paste the animation in the Merge Node's 'Mix' attribute.
3) Switch the Merge Node into a Multiply.
4) Disable the multiply Node.
Option 2:
Replace the FrameHold with a FrameRange Node set at the single frame you would like to roto with.
Option 3:
Replace the FrameHold with a Read Node referencing the single frame you would like to Roto with.
Reproduced by support
Nuke11.0v1 - Windows 7 - Mac10.12 - CentOS6.9
Nuke10.5v6 - Windows 7 - Mac10.12 - CentOS6.9
Nuke10.5v1 - Windows 7
Nuke10.0v5 - Windows 7 - Mac10.12 - CentOS6.9
Nuke10.0v1 - Windows 7
Nuke9.0v9 - Windows 7 - Mac10.12 - CentOS6.9
Nuke9.0v1 - Windows 7
Nuke8.0v7 - Windows 7
Nuke7.0v10 - Windows 7 - Mac10.12 - CentOS6.9
Earliest version tested
Nuke7.0v10 - Earliest version we regress
Expected behaviour
Nuke to render the footage without errors and graphical glitches.
Actual behaviour
Nuke recieving an error on render, either cancelling or causing graphical glitches in the result.