[Qgis-user] MVP solid 3d

[Gerald Kogler]

Hi!

I'm trying without success to visualize a simple solid 3d object with 
QGIS 3d Map View. The geometry is of type PolygonZ, but the 3d viewer 
only shows it in 2 dimensions without Z values. All triangles are shown 
on a plain.

The layer definitly does have Z values, using for example 
geom_to_wkt($geometry) does show me WKT values like:

PolygonZ ((204594.00012206999235786 496779.0001220700214617 2998679.5, 
204771.00012206999235786 496783.0001220700214617 2998679.5, 
204881.00012206999235786 496802.0001220700214617 2998679.5, 
204594.00012206999235786 496779.0001220700214617 2998679.5))

What do I miss, anything in the configuration which could be wrong? I 
only manage to show the third dimension using extruding, that works fine 
for example to show buildings from OpenStreetMaps.

Anybody knows about a dummy Getting Started tutorial beside the official 
QGIS docs about 3d Map View in order to make a really basic example work?

Thanks for your help
Gerald