Subtracting NOT solid model from solid topography

Hello everyone,

I am currently working on a project in Revit and the task I am about to do is extremely complicated to do in Revit, so I am trying to do it in Sketchup and export it. Now that I am in Sketchup it turns out it is not that simple of process also in Sketchup.

I want to subtract a stairway and walls around it(basically a proposed landscape) from an existing topography.

There are a couple of terms that I have to keep in mind:
The topography is solid(using the Fixit 101 plugin)
The model(stairbox and rest) is not solid. I tried to make it solid but it looks like it is not possible.
First I tried “Subtract” from Solid tools, however, as it is not a solid(the model) it is not working.
Then I used “Stamp” and “Drape” but none worked correctly. Stamp does not create all the edges(if it did, it is by far the best option I think) and Drape only drops the lines on topography, which is not what I am looking for.
I want to cut the whole topography in spots where new construction is going to be built. then I can copy the model itself in place.

This is the result when I used the Stamp tool and as you can see lots of my model lines are not stamped on the topo.

What does the model have that you can’t make it a solid group?

Have you tried ‘Intersect Faces’?

the model does not have anything special. only a couple of hundreds of boxes as stairs and some walls.
And, intersecting faces does not work that well, as topo and model are not in the same elevation and have slopes. Anyhow, I scaled up the model by 100x to have common edges with topo everywhere, intersecting causes SKP to crash. Other than that, I do not think intersecting works fine, because I want to actually dig a hole in the mountain and then add the model, so somewhere on the topo may be higher than the model and some points lower.

‘Intersect Faces’ should work.

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Well, I tried intersecting, as shown in the image above, there is too much geometry to deal with and the result is not gonna be good, also I checked that there are lots of failed edges that do not make any geometry and cannot be easily dealt with.

I really thinking about a way to get a subtract-like result

Why does it look that way??
In your screenshot you can clearly see that a lot of the boxes are open on the underside. That’s a no-no for being solid but is also easily solved…

only if I could find a way to make this whole shape( or even in parts) a solid. It is not a tiny model so checking edges one by one is not an option…

If you create your model correctly, it could also work with Solid Tools, but more than likely ‘Intersect Faces’ would work.

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Why don’t you make 1 box that outlines your heap of boxes and subtract that from the topography?
Like @mihai.s showed you…

It’s clearly a modeling issue, if you had modeled it properly you could do it easily. If you share your file probably we could help you or advise you to do it well.

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yeah I noticed that, But the point is closing it all does not make it solid, right? because there are all those boxes connected to each other, so not a solid still after that.

Sure thanks,
Here is the file.
Please note that I exploded the whole model somewhere in the process, so I copied a grouped version on the side.
Untitled.skp (528.7 KB)

PS: the real spot for the model after excavation is somewhere like this image below

There’s more to it but a closed box can certainly be a solid. If all boxes are solid you could use them with the solid tools…

aaa…note sure,
I tried to boxes sticked together (exploded) and it did not know it as a solid

Why would you do that? That makes it much harder to work with.

Because I am a stupid moron!
I switched from Revit to Sketchup to do this process exactly using this method and as soon as I got to Sketchup I totally forgot my thoughts and fell into the marsh I am in now !!

Thanks mate I think that works,
Although there are some spots in between that shouldn’t be cut, but I think I can deal with those more easily

If each individual box or part is solid you can use ‘outer shell’ or ‘union’ to make it all into one giant solid.

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You’ve got some seriously messed up / sloppy modeling which is why your main group isn’t easily becoming a solid. Lots of extra lines / surfaces / internal faces.

Lots of this going on…


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yeah, makes sense. It was drawn on an imported PDF to Sketchup and different push-pulls and different moves and other stuff. I was expecting such a mess.
Maybe after cutting the hill using the simple method I recreate this model too.