Camera Rig Rail Position on Rail stuck at Default when Attached at first frame

Any ideas as of why the attached actors do not move when attached to a Camera Rig Rail on the first frame of the Shot? Everything works fine if the attachment happens after the first frame or if the Camera Rig Rail is Possessable. Otherwise the attached actor stays static at the Camera Rig Rail’s default position. This issue only appears during MRQ Renders (playing the sequence In-Editor and PIE work as expected).

Try dragging any animation track start from 0 to -1

Hi @scottunreal. I’m not using Animation tracks, just an Attach track binding a (possessable) BP Actor to a (spawn) Camera Rig Rail. I tried moving the initial Current Position keyframe on Cam Rig Rail to -1 and the Actor’s Attach track back to 0 but still get the same issue when attaching at frame 0.

What I noticed in world outliner is that when the Attach happens at frame 0, the system fails to re-spawn the rig rail during Renders and the Actor remains attached to the (spawn) In-Editor version of the Rig Rail (while Sequencer is probably moving the position of the PIE version of the rail), AND when the Actor is attached at frame 1, the system spawns a new rig rail at runtime and successfully re-attaches the actor to this new version of the Rig Rail.

As if, MRQ is trying and failing to attach the Actor before it creates the runtime version of the Rail.

A couple of notes:
At least with 4.26 there were odd differences between attaching in world outliner and attaching in Sequencer.

Is it a requirement to use a spawned camera rig rail? Spawned of course doesn’t exist beyond your in and outs and can sometimes have issues reconnecting>

MRQ requires an initial position to move from, otherwise, the camera will be odd.

Yea, I may end up converting them all to Possessable when I finish the project if the issue remains unfixed by then. Oddly enough the same project was working fine on 4.27.

I am having this exact same issue.

I have a car attached to a camera rig rail that is animated using Current Position on Rail. The animation is keyframed and looks great in the viewport, but when I try to render in either Deferred or Path Tracer the car just stays stuck at the beginning of the rail. My camera animation are rendered, just not the movement on the rail.

All actors in the sequencer seem linked. None of them are red. This is very frustrating.

Anyone got a fix?

Make sure there is no logic taking control over the car. If you hit Play does it work? Can you try and attach the car to an empty actor or something and have that actor be driven by the Rig Rail? A lot of times player controller takes over the input controls.