Laying a level, but sloped, road surface

Good Evening

Another modelling challenge from me :wink:

At the moment I am imagining that this is actually quite easy, but I seem to be having a day of being a complete donut, and can not seem to think how to do it.

Anyway, attached, via Dropbox, is a model which contains terrain created from Points, and using TopoShaper. I have shaded the road surface a different colour to aid in the description.

As can be seen, the whole site is on a slope, and in the area where the contours are close and the land is steep, the road falls away to one side. I reality, this has been built up to create a flat, but sloping road, if that makes sense, and not one which would result in cars falling off the side. On this problem side, there is a stone retaining wall next to the footpath with a 4m drop to the level below, approximately. (Photograph attached. The retaining wall is covered in the vegetation shown).

Essentially I’m struggling to figure out a way of levelling/building up this road, while still maintaining the overall slope down the hill.

I have used Sandbox Tools to Drape the linework onto the terrain.

Anyway, help would be greatly appreciated in pointing me in the right direction. I seem to be getting more of this type of modelling associated with projects and so it will undoubtedly come in handy in the future.

Kind regards


I’m on my phone at the moment so as a thought from your description, what about eneroths upright follow me.

Eneroth’s Upright Extruder will do a lot of the work for you, you might need Fredo’s Curviloft or Tig’s Extrusion tools to make the junctions.
But here’s a start, I used the top edge of the road and smoothed it somewhat by drawing straight lines over the biggest dips.


Hi @Box

That’s brilliant. Thank you.

I’ll have to download Eneroth’s Upright Extruder, but that’s exactly what I need.

I’m assuming you drew the road profile at the edge of the model first?


I drew the profile outside the group, then went in and selected the path and copy/paste in place outside the group, cleaned it up a bit and extruded.
So the whole road is outside the terrain group.

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In addition to Box’s recommendation, you can use Fredo’s BezierSpline extension to help smooth out the extrusion path and control the number of segments.




Thank you @Box and @ChrisDizon

Eneroths Upright Extruder works really well. I tweaked it slightly by drawing my face perpendicular to the path and it gave me what I need. Pretty ■■■■ close to the surveyed height too.

I didn’t use Bezier Spline for this as the road is quite uneven anyway and wanted to keep it like that. Will be using it for the next stage though.

So, the next part I have to sort is the pathways and the junction with the other road which goes down hill also. I think I have a plan for both and it involves using a combination of Bezier Spline and Curviloft plus Fedo’s Joint Push Pull.

I’ll post the result when it’s done.

While this is for a Client, I’m also using it as a learning process as I want to get better at terrain modelling.