Boolean a landscape with a path; workflow help

Hi there :slight_smile:

I will try to keep this as short as possible; please forgive the long post.

This semester, we were required to make an equal access path on a designed topography.
The workflow was like this:

  1. In AutoCAD, draw contours using polylines
  2. In AutoCAD, draw a path’s outline with vertices at ramp endings and landings
  3. In 3ds max, elevate the landing vertices and contours to specified elevations.
  4. In 3ds max, use the contours to create triangulated mesh solid for boolean
  5. In 3ds max, use path outline to create ‘bevel’ used to boolean with the solid mesh
  6. Render, and contour the solid boolean result.

This workflow was very problematic due to 3ds max instability/unreliability. I spent many dozens of hours failing.
I am wondering if something similar can be achieved in Rhino. The biggest question is how to set up the boolean components.

  • The topographic mesh can be created with Delauney and converted to Polysurface.
  • The path with a tapered ‘bevel’ is where I’m lost.
    – How does one create the purest boolean path component given that the path outlines have varying elevations. Sweep/loft/offset/ribbon offset/GH?
    – Can it be done as a single component, or would it have to be multiple booleaned together?
    – How does one create the path taper?
    – Can the boolean landscape take on the material id of the bevel operands?

If you have any ideas or thoughts about the above, would be greatly appreciated. This is very useful for landscape design.


Hi Jeremy -

I would do this strictly using meshes.

If you can create the path centerline, you should be able to sweep a tapered rectangle as a profile and use that as cutter and filler.
You might want to attach a file.

1 Like

Hi Wim,
Thanks so much for your advice; I will try it. I just want to clarify a few things

  1. Do you mean to sweep the tapered rectangle; then convert that to mesh as well for boolean with the Mesh topography? Or leave the tapered cutter/fill as a polysurface for boolean with mesh topography?

  2. With this tapered sweep workflow; it seems like that the separate parts of the path would need to be created as individual components instead of a single solid for boolean. I’m not sure how 3ds manages its single ‘bevel’; but would you recommend I boolean the individual polysurfaces together before attempting boolean with the topography? Or to do them separately?


Hi Jeremy -


I’m not “seeing” separate parts of a path. If you say they can be booleaned into one, how can they be separate?

I don’t know if it comes across clearly through these images:

In this image, you can see the editable spline and the landing vertices which have been raised to various heights. Also note that it’s not one linear path; bur rather an outline of many path segments; raised to various heights. This is what made me wonder how they make it into a single solid in one modifier.

Then the ‘Bevel’ modifier on this spline produces the above.

If you increase the bevel outline to an extent where the geometry overlaps, it ‘uncaps’.

In Rhino; sweep, loft and planarsrf can combine to achieve something similar it seems; but as seperate parts which are used together as boolean operands.


Hi Jeremy - can you please post your file, even a simplified version of what you are working with, or send to, with a link back here in your comments?


Hi Pascal

Here is the redacted file with the components ready to boolean.

Topography boolean with path.7z (758.8 KB)


Sorry, nothing I can do with a .max file…


Hi Pascal,

Sorry, I didn’t know what file type you wanted. 3ds has it’s own internal processes which get converted to meshes when exporting.
I’ve attached a DWG and 3dm with a mesh and curve.

DWG and 3dm.7z (13.0 MB)