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Slab and Wall Intersection Issue

Hi All

I’ve come upon a modelling issue where I have a tapering floor slab which i’ve modelled with a SEO using a morph to cut the slab.

A part of the wall that the slab sits on is now missing, The BM of the slab and the wall has the same PI of 450. but the wall is still reading the extents of the slab and not the cut section.

The only way i can find to remedy this is to convert the slab to a morph (with slab class).

Is this the only way to solve this issue?
Robert Thompson
Ackee Workshop
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Gerald Hoffman
Have you tried using a roof set to zero depth for your operator?

"The simplification of anything is always sensational" GKC
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Check this wish and the two links to the corresponding threads for explanation.

It's cases like this where "but then" applies when looking for workarounds:
1. You could adjust the slab perimeter so it doesn't go above the wall (would depend on the project's design intent) but then you could have wrong slab volumes and the wall might not be shown correctly in a perpendicular section.
2. You could use a profiled beam for the tapered part of the slab, but then you'd have to keep track of two distinct elements and clean up the junction in floor plan (a case where I think fills should clean up when two elements have the same BM, like in elevations) and when exporting to IFC, for example, you'd have two elements for a single slab.
3. You could solve this if you have the walls that fall under the tapered part of the slab in a different layer with distinct intersection group and then use SEO (between wall and already SEOed slab) to cut out the remaining part of the wall.

Best thing would be if PBC would work after a SEO has been done to a certain element because SEO are element based.... but then other things might happen.

Best regards.
Laszlo Nagy
Community Admin
Community Admin
I would handle this situation by creating a Morph for the missing part in the Wall and performing an "Addition" SEO with the Wall as Target, the Morph as Operator. This way the missing gap in the Wall will be filled. Also, since the geometry of the Morph body would be added to the Wall geometry, it will be seamless so you will not see any unneeded edges appearing in 3D.
In the attached image I selected the Morph I added and you can see that a SEO Addition was performed between it and the Wall.
The SEO operators are normally placed on a hidden wireframe layer (so even when the layer is shown the SEO cutting bodies are shown in wireframe).
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Erwin Edel
Depending on the geometry of the entire thing, I'd use a complex profile beam. The beam will interact with slabs, walls etc the same way the slab would and having the cross section as an easy to edit fill rather than having to deal with manipulating morphs is, in my opinion, more productive over the course of the project and any changes to come.

If it's a tapered shape that appears in many places. but is not consistent throughout the project, it might be faster to manipulate a morph.
Erwin Edel, Project Lead, Leloup Architecten

Windows 10 Pro
Adobe Design Premium CS5
sinceV6 wrote:
...a case where I think fills should clean up when two elements have the same BM, like in elevations) and when exporting to IFC, for example, you'd have two elements for a single slab.
Oh yes, is there a wish about this? Especially for the floor plan clean-up, you could assign the two elements for an IFC group - that's something. | actively using: AC25-27 INT | Rhino6-8 | macOS @ apple silicon / win10 x64

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