Extrinsics and Coordinate Transformation Conventions (OBTransform, OBExtrinsic, ...)

[rafaelspring]

Hello, what are the conventions for the following struct (from ObTypes.h)?

typedef struct {
    float rot[9];    ///< Rotation matrix
    float trans[3];  ///< Transformation matrix in millimeters
} OBD2CTransform, ob_d2c_transform, OBTransform, ob_transform, OBExtrinsic, ob_extrinsic;

Is the rotation matrix stored row-wise or column-wise?

When using auto extr = sourceSP->getExtrinsicTo(targetSP), what is the convention for the extr object?
Is it the transform that takes points

1. in source frame coordinates to target frame coordinates, or points
2. in target frame coordinates to source frame coordinates?

Thanks!