Help with contours - landform

Reduced file size for upload.3dm (5.9 MB)
Hi there,

I’m trying to run contours on my landform but I’m having issues with boolean union failures and I can’t troubleshoot as the error bubbles aren’t showing up and Analyze is not showing any naked or non-manifold edges.

The reason I’m trying to boolean before I contour is that I have several surfaces that I need to contour together. So my thinking was that I would extrude them all (to boundary - straight) to create solids, then boolean union into a single object, extract the top srf and contour that.

I created tapering edges along the curves of most of the surfaces so they would intersect when I extruded them, but I can’t seem to get them to boolean and I’m all out of ideas.

Any help would be amazing!

do you mean these shapes to be extruded?

I just selected, (not the thin vertical), extruded (gumball), boolean union, trimed with a line.
hth Ferry

I need to boolean everything in the file i shared so I can extract and contour just the top surface. Perhaps those thin verticals are interfering with the boolean though so I’ll try omiting them now and have another go.

There are a lot of things to boolean, too so perhaps the order of booleans is confusing rhino - i might try them sequentially rather than all together as a group.

thanks for trying anyway @ferry59

Hello - Boolean operations will not be your friend here, I would say - Trim and Split and Intersect will be helpful though. Boolean opertations typically invove closed, intersecting objects or at least ones that intersect fully - what you have here is a bunch of independent surfaces - that’s fine, but it looks to me like even if you Join as much as you can, you won’t have a setup that is happy with Booleans.


Thanks Pascal. My issue is that I need to contour them all together, so I need them to be read as a single surface. I don’t know how I would do that using Trim and Split and Intersect?

I’m *very slowly making progress with Booleans, but I’ve hit another roadblock I can’t seem to get past with the amphitheatre section that ferry59 had a look at above. File is here.

Reduced file size for upload.3dm (3.0 MB)

I’m trying to boolean each of these pieces of geometry here into a single object, whilst retaining the top srf structure but I just can’t get it. The second step from the bottom appears to be cause of the issue as everything else will freely boolean depending on the order of operations. I have tried Intersect to identify the issues, and I found a section that appears to be broken but I can’t seem to fix it

I took a closer look onto this, the thing was, that yesterday I imported your file into my default template whitch has tolerance set to 0.001. Then exploded the geometry, rebuilt edges and joined again.
So opening your file today I saw, that the tol is set to 1. You have to decrease it, 0.01 was enough for me.
The 6 steps could be booleaned into a single closed polysrf, the enclosed faces of the blueone where trimmed. Both can be joined into a closed polysrf.

RE_Reduced file size for upload.3dm (1.3 MB)
(Texture removed)
Kind regards Ferry

Tolerances! That’s helped me a lot. Thanks @ferry59