Help understanding point cloud stitching & rig.json for LiDARs ( on Orin)

[Jis]

Please provide the following info (tick the boxes after creating this topic):
Software Version
DRIVE OS 6.0.10.0
DRIVE OS 6.0.8.1
DRIVE OS 6.0.6
DRIVE OS 6.0.5
DRIVE OS 6.0.4 (rev. 1)
DRIVE OS 6.0.4 SDK
other

Target Operating System
Linux
QNX
other

Hardware Platform
DRIVE AGX Orin Developer Kit (940-63710-0010-300)
DRIVE AGX Orin Developer Kit (940-63710-0010-200)
DRIVE AGX Orin Developer Kit (940-63710-0010-100)
DRIVE AGX Orin Developer Kit (940-63710-0010-D00)
DRIVE AGX Orin Developer Kit (940-63710-0010-C00)
[x ] DRIVE AGX Orin Developer Kit (not sure its number)
other

SDK Manager Version
2.1.0
other

Host Machine Version
native Ubuntu Linux 20.04 Host installed with SDK Manager
native Ubuntu Linux 20.04 Host installed with DRIVE OS Docker Containers
native Ubuntu Linux 18.04 Host installed with DRIVE OS Docker Containers
other

Issue Description
<I’m new to DriveWorks (and I am not a computer scientist, this is all still very new to me ..) and trying to stitch multiple LiDAR point clouds. I followed this example:

DriveWorks SDK Reference: Point Cloud Stitching

There’s a placeholder in the code:

// get transformations for each point cloud

I don’t know what exactly should go here. Do I need a rig.json for the extrinsic transformations? If yes, where do I get it from? The docs mention LiDAR self-calibration and rig configuration, but I’m still stuck because it always seems like I have to write a rig.json by myself? I don’t even know how it should look like.

So far I only managed to run the lidar_sample_replay example for a single LiDAR. Accumulator makes sense, but I’m stuck at stitching.

Any tips, hints, or example workflows would be hugely appreciated — even just pointing me to the right documentation sections. At the moment, I often struggle with knowing where to find the information I need.

[SivaRamaKrishnaNV]

Dear @Jis ,

Do I need a rig.json for the extrinsic transformations?

Yes. rig file describes the extrinsic transformation between Lidar sensor and rig, the transformation can be extracted from dwRig_getSensorToRigTransformation API call. Please see PointCloudProcessingSample::initStitching() in /usr/local/driveworks/samples/src/pointcloudprocessing/PointCloudProcessingSample.cpp for reference

If the transformation is not given then it returns identity transformation.

See https://developer.nvidia.com/docs/drive/drive-os/6.0.10/public/driveworks-nvsdk/nvsdk_dw_html/group__rig__configuration__group.html#ga80d66aeafcb7e2c2c700b8735a9e1327

Please check DriveWorks SDK Reference: Rig File Format for rig file format. Also, you can take a look at rig.json files shipped with DW samples data folder for reference.