Hello barnabu,

try this:

open model in GEv4
right click the placemark > select properties >select style,Colors tab >select share style button > select OK at the bottom of the Style,Color window and repeat the process..

on the 2nd run, when the Style,Color options window opens change to the following.

for line options
color box=white
width =.3
opacity =20%

for the area options
color box = white
pulldown box = filled and outlined
opacity =80%
random colors box = checked

click ok at bottom of window,
if for some reason the changes do not take , run the process again......


color selection box for area fills: (building colors)
white = random all colors
green = random green hues dominate
brown = random brown hues dominate
red = random red hues dominate
etc .....


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perhaps in the future GE will provide this process as an option for the buildings layer so that we will have custom viewing preferences as an option.