We have using AR foundation with both horizontal and vertical plane detection to place the 3d object in real world. Horizontal plane detections are working fine but vertical plane detection is less accuracy than horizontal plane tracking and also objects are floating in air while place the object in vertical plane detection.
How to fix the above issue to place the 3d object more accuracy in vertical plane detection.
AR Foundation allows you to work with augmented reality platforms in a multi-platform way within Unity, using the ARKit implementation of plane detection on iOS and the ARCore implementation of plane detection on Android. Unity does not implement plane detection, so to address your concerns about accuracy, please refer to your provider’s forum.
If the wall is white, then the tracking quality is going to be poor. A phone camera is searching for patterns in floors/walls and white walls do not have any pattern so that is why you have difficulties with vertical plane tracking. LIDAR-equipped phones can solve this issue, but you must wait for them to be widely adopted.