Functions: adding lines/polygon in viewer+ displaying point cloud on existing viewer

[hduonggithub]

Hi @heremaps

I have been impressed with your tool but there is a limit that the tool cannot be used much in community. I do believe that if the tool can have more functions in the following, it will be definitely the incredible tool

1. Adding a method to display lines/polygons/planes together with point cloud.
2. To load a new point cloud to an existing viewer
3. To be able to display multiple point clouds together on an existing viewer.

Thanks!

[mbcel]

I think the Viewer().load() function can load new points on an existing viewer. However this changes the camera view instead of keeping it at the current location. I am currently trying to find a work around how this could be done without affecting the camera view.