ARKit drift of position and poor tracking

Development Platform & Builds XR Development
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1

Using the ARSample from the 4.17 blog as a sample, we set up our project to draw a character.

The ARSample scale of objects is pretty large so it is hard to see the drift. If you scale the objects down to 0.1 (like 6-8 inches tall) you will see they are not locked that well. There is some performance issues to it since if you set the object like the sphere to moveable so it is dynamically lit, it is much worse. This is a pretty simple scene.

Our scene has 1 skeletal mesh character and one object that acts as a mask (has the camera material on part of it).

With that it works but it looks like there is a several frame lag on the tracking with it drifting all over.

For reference, we have the exact skeletal mesh character on Unity ARKit and it is rock solid. No drifting really at all with the skeletal mesh dynamically lit and some effects.

Anyone have any tips for potential fixes for making the UE4 ARKit tracking more stable and reliable?

2

I was told by Epic and Apple about the flag “ar.EnableLateUpdate,” Turning this off significantly improves the tracking and removes the frame lag I was seeing.

3

Awesome Jeff, thank you for sharing :slight_smile:

4

Where I can find the flag “ar.EnableLateUpdate”? In Blueprint or C++ code?

5

It is a console cvar. You can set it in blueprint or in code (or in ini file).

6

You can also do a 4 finger tap to bring up the console and type “ar.EnableLateUpdate off”.