Problem with merge tool in 3D

[MatusKolenka]

I am working on 3D map of the city. All buildings are visualized from polygons. My task is to connect polygons into buildings. I tried it with the "Merge" tool, but i have big issues with it.
Firstly,as you can see on the photo, after merging polygons, the whole shape is distorted or even completly disapears.
Secondly, as i try to merge for example wall with roof, error "cannot merge overlaping polygons with differing z values. 

I will be very grateful for your time and advices

Best regards

[MatusKolenka]

After following your steps, all my polygons have 4 vertices. But in my case, i need also polygons with only 3 vertices (such as roofs). Also, i tried to generate height with geoprocessing tool "Generate elevation bands", but unfortunetly, this tool its not licensed to me.

But i am trying different strategy now. Instead of working with polygons, i visualized all my geometry with points, where i can calculate height. I can merge points into specific buidlings, but i do not know, how to create polygons from points.

Thank you for your time and advices

[Faiez]

Hi!

Here are the methods to convert polygon to points and  points to polygon:

1. Convert polygon to points

2. Convert points to polygon.

Best,

Faiez