How do I get the top surface of the elements and the outline of the Difference?

[Dornan_Luke]

I selected the slab and beam and converted the surface.
But I don’t know how to handle the top surface and the difference.

Any advise is greatly appreciated.

TSF-0357-Q1.dyn (6.9 KB)

[lucamanzoni]

Something like this should work:

Basically I filtered the surfaces according to the Z elevation of their middle point and took only the upper one.

[Dornan_Luke]

Thank @lucamanzoni
However, what should I do if I ask the slab to do a multi-object difference?
Thank you!

[lucamanzoni]

You are welcome. In that case you have to use Solid.DifferenceAll

http://dictionary.dynamobim.com/#/Geometry/Solid/Action/DifferenceAll

[lucamanzoni]

This way should work better:

you need to merge the solids to subtract with Solid.ByUnion

[Dornan_Luke]

Thank @lucamanzoni

[Ecenurc]

I tried out the solution. I want to add this.

When I tried to get the outer curves of the top surface, the “Surface.PerimeterCurves” node didn’t get all of the outer curves. From the package “Spring Nodes” this “Surface.Outer PerimeterCurves” node worked out well.