extend Node class so viewports don't break the scene hierarchy

[DrAlta]

Describe the project you are working on

Trying to implement object highlighting as described in https://www.youtube.com/watch?v=SMLbbi8oaO8

Describe the problem or limitation you are having in your project

camera's only render to the nearest viewport above the. If you put a viewport above them than it breaks the transform hierarchy so if yo want two camera at the same place you can't just have the two camera's children of the same node and the move that parent node. This also breaks using RemoteTransform(as reported @ https://randommomentania.com/2019/07/godot-color-mask-tutorial/ )

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Change Node class so that it passes the transform down the scene hierarchy

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

This is an alternative to #2825

transform as Node2d or Spatial
Set a Node as it's child. then set another Node2d/Spatial as the child of that node then and have the grandchild node inherent the transform of top Node2d/Spatial.

If this enhancement will not be used often, can it be worked around with a few lines of script?

Yes

Is there a reason why this should be core and not an add-on in the asset library?

I don't because you can change how classes work in add-ons.

[YuriSizov]

So far you've created 3 proposals to solve one issue, with at least 2 of them (#2825 and #2826) breaking the rules of the engine and therefore not feasible.

However, the effect you want to achieve has nothing to do with multiple viewports or cameras and has everything to do with multiple passes with shaders, which are covered by #495, #895, #2196, #2675. So I don't think any of your proposals describe a correct approach to solving this problem.