[seghier]

Just an example :
https://www.dropbox.com/s/bpu80lvz2sd0b ... e.rar?dl=0

[ababak]

Thanks, that's another nice trick! I tried using Maxwell Scatter as I was suggested by Fernando, but then I loose an ability to map colors. I'll try your method now. Wish it worked without ugly workarounds.

[seghier]

when you create an new surface inside the object is better do not group them but drag the new surface under the original object and hide it
that is better when scale ; rotate and translate