Rhino Hatches color and boundaries to GH

Hello,

I'm having a hard time trying to generate large scale city model from WMS files in Qgis to RH and GH.

My Qgis tools allowed me to create dwg/pdf files with a set of polygons and a filled color in scales of grey showing the height of the each building. I've been able to import this dwg in rhino but the polygons are imported as hatches and i'd like to get those hatches and their respective colors into GH to script a simple extrusion from greyscale definition.

Is there a way to get those hatches and their own colors into GH?

The screenshots bellow are showing an example of the dwg file i want to get into GH and the model i already did with an other method (scripting the boundaries with some numbers as Guid, but this is taking way too long to match numbers and polygons)

Thank You for your advices ! 

Dam