MRQ assert - failed to evaluate camera to create cur/prev camera locations

Development Cinematics & Media
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1

Hi,

we encountered a problem in our project. Whenever Movie Render Queue is used to render Level Sequence in the Development mode, assert fails:

“Failed to evaluate camera to create cur/prev camera locations. No camera actor found on Eval Tick:” (MoviePipelineTiming.cpp, line 237)

I tried to recreate the Level Sequence from scratch, recreate Shots and Cameras, but the error persists. However, it does not happen when there are no nested Shots - the Level Sequence is simple with track Camera Cuts only.

I attached repro project. To replicate it run the application in the Development mode and try to record video via Record button. Note: It shows also another error with Flags because of CopyFrom() but it is resolved in our project.

Could you advise us or explain the error please?

Best regards,

Petr Opletal

2

Can you try and enable first-frame motion blur emulation?

3

Disable “Use Camera Cut for Warmup”. Its not getting data to generate motion blur on the first frame for whatever reason. If that does not work you can try and extend the camera cut. According to the dev MRG handles these sorts of cases better then legacy MRQ so that may be an option as well.

4

Unfortunately 5.3 is out of the support range so if we need engineering help our resources might be limited with the upcoming release priorities. We’ll do our best though. Can you help me repro this on my end though? I opened up your project and went into PIE. I can hit the Record button and the Play button without any errors or failures. So I am unsure I am doing this correctly.

5

Ok maybe we are missing each other on step 2. Very specifically, I am:

  • Generating the VS project. The uproj is associated with 5.6 so I am using 5.6.1.
  • Opening the sln in VS2022
  • Setting the start project to MRQ_Play_Test_V2
  • Setting it to Local Windows Debugger and hitting Play
  • In UE, going into PIE
  • Hitting Record.

Do you see anything I am not doing correctly?

6

I am running it like this and see no errors. I asked someone else to have a look as well and neither of us could repro. Could you make a video or something? Perhaps we are missing something obvious.

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7

Hi Shaun,

yes we can try but we are not sure how. We tried to play with several settings in the MRQ preset (like enabling “Render Warm Up Frames”) with no luck. Anyway, we do not use motion blur so we are not sure how it could help us.

Could you please elaborate?

Thank you.

Petr Opletal

8

Thank you for your suggestions. We tried both to disable “Use Camera Cut for Warmup” and also extend the camera cut but unfortunately it did not work. MRG is not an option for us because we use UE 5.3.

Is there anything else we can try?

9

We tried it once more our end and it should be replicable:

1. Generate VS project.

2. Run the project from VS in the “Development” solution configuration.

3. Press the record button.

4. You should see the MRQ assert.

Note: As mentioned in the first post. It shows also another error with Flags because of CopyFrom() but you can ignore this one.

10

Yes, the second step I wrote is important. You have to select “Development” solution configuration. It works fine in the “DebugGame” solution configuration.

11

Thank you for being so helpful. We tested it on several machines and it was reproducible. I’m attaching repro case without first “CopyFrom()” assert. So now it contains only one related to this post. I’m also attaching video made by my colleague with exact steps from unzipping the project to the assert.