Problem summary: Expressions that reference image attributes like width and height can negatively impact performance when used on specific knobs
This issue is known to affect the following knobs, but may also impact other knobs/nodes:
mixknobs (present on nodes such as Blur, Merge, Defocus, CopyRectangle, etc.)
opacity knobs (present on nodes like Text, Radial, and Noise)
the Switch node's whichknob
Customer reported version: Nuke 15.2v6
Customer reported platform: Rocky 8
Steps to reproduce: 1) Open the attached example_file.nk in Nuke 2) Scrub to different frames in the Viewer, and note Nuke's responsiveness 3) Connect the Blur1 node to the networked Read node 4) Observe how scrubbing through the Viewer is now significantly less responsive, even though the Viewed section of the Node Graph has not changed.
Expected behavior: All knobs in disconnected sections of the Node Graph should be able to reference image attributes like width and height without inhibiting Nuke's playback/Viewer responsiveness.
Actual behavior: If certain knobs have expressions which utilize width, height, or other similar attributes, Viewer performance can be negatively impacted even though the Nodes are not connected to the Viewer and their Properties are not open.
Workaround: One option would be to Localize the networked media, which improves performance. Alternatively, getting the width/height from a FrameHold node also seems to improve the situation.
Reproduced by Support in: Nuke 16.0v6 - Windows 11 Nuke 15.0v1 - Windows 11 Nuke 14.0v1 - Windows 11 Nuke 13.0v1 - Windows 11
Unable to verify on additional operating systems due to networking constraints
Earliest version tested: Nuke 13.0v1 - This issue appears to be in all tested versions of the product