Contour surface offset

[azz00]

Hi Everyone,

I am currently trying to produce a 3D model of Sheffield City centre to be CNC milled this coming week.

I have done everything including the site contours, buildings etc.

However, I am struggling to find a solution to offsetting the roads by -0.5mm. Because the surface I have generated is a smooth contour, I cant find a way to cleanly pull the roads down?

I have attached a link to the road layout so you can understand what I have so far.

I have tried the joint push pull but it errors everytime. I am assuming that this is because the geometry is imported from Revit and theres something wrong with it?

https://www.dropbox.com/s/c5hn5s9i4er6dhp/road%20layout.skp?dl=0

Thanks for any advice!

[pilou]

Pull down or offsetting ?
That is not the same thing!

Scale * 1000
Seems works with Projection by Didier Bur
But you must repair some little gaps !