how to keep fixing ground plane to X-Y plane?

[Suzy]

hello,

I am using a handheld scanner Kinect V2 for room interior scanning.

I have searched the previous question about" Fix ground plane to X-Y plane"& "rtabmap don't recognize the ground~~ ".
I activate "Align odometry with ground on initialization" option in Odometry panel, and also force 3DoF(x,y theta) in graph optimization panel.

But I found that the plane can not be kept fixing into X-Y plane, which plays a role in my process.

As you can see, left side of ground is fixed, but right side of ground is tilted.

[matlabbe]

Hi Suzy,

you should not set "force 3DoF"/"2D slam" (in graph optimization or motion estimation panels) for free hand-held trajectory. There is no ground detection option to always keep aligned the ground with the X-Y plane, only at the start with the corresponding odometry option that you activated. Over time, because of the drift, the ground may not be aligned exactly with the first cloud.

Indeed, having an option to add constraints to graph to keep the ground aligned would be great (when we assume that the ground is always a plane at the same height).

cheers,
Mathieu