[SOLVED] Object starts flickering during tracker animation

[Coppel.Damien]

Hi everyone,

I'm having troubles with the tracker tool and the video grabber.

In my scene, I've got an object (made of multiple meshes) and multiple cameras as child nodes in the hierarchy of that object, so when I move the object, the cameras (PlayerDummy) move as well. The cameras are facing outward from the object but some part of the object are visible in the camera view as their FOV is quite high.

I've set up a small animation in the tracker tool : the object takes off, rotates a bit toward the ground on its pitch axis, and starts moving forward. I then use the video grabber tool to record the view from one of the camera attached to the object during that animation.

The images sequence is rendered well but unfortunately the object starts randomly flickering during the animation and some parts of the object are invisible for a brief amount of time.

Does anyone know how to fix this and prevent the flickering ?

[davide445]

Hello Damien

I have had a similar problem when there was two meshes very near and intersecting in some point. Caused from CAD import. 

[morbid]

Hello @Coppel.Damien,

May I see a test scene?

Are you using setEnabled option for the meshes in the track file?

Thanks.

[Coppel.Damien]

@davide445 Hi, have you found any way to fix it ?

 

@morbid Here you go, here's the scene in a video file. As you can see, it just starts randomly flickering at some point in the video, some parts of the model disappear and reappear quickly.

In the track file I'm only using the position and rotation parameters of the object, nothing else.

I did some more tests, I placed the back camera further away from the object, I rotated the camera towards the object, and in this configuration , no flickering happens.

I wonder if this is maybe linked to the camera and its Z-Near value ? I tried to change the Z-Near value (by increasing then decreasing it) but the flickering still happens.

Right now the Z-Near value of the back camera is set to 0.01 (it has to be at a low value because I need to see the object on camera without it being clipped) and the FOV is set to 108 degrees.

 

 

Edited September 20, 2019 by Coppel.Damien

[davide445]

@Coppel.Damien I manually corrected the meshes alignment so to avoid crossings. 

Edited September 20, 2019 by davide445

[morbid]

@Coppel.Damien Is it possible to retrieve a scene with the model and track file?

This flickering effect can be produced by the mesh itself.

UPD

I did a couple of test with Oil Platform demo. Used camera (with the same settings as your one) and attached to the helicopter for video grabbing. Worked fine. No flickering. I need to see the scene.

[Coppel.Damien]

@morbid I finally managed to solve the problem by using a workaround, I used the "Create mesh" option in the editor on the object to make it whole instead of just a combination of multiple meshes.

After doing that, the flickering didn't occur anymore. It seems that it was due to the meshes themselves.

Thanks for your help.