Wish: extract slab boundary quickly

It’s possible to edit the control points of slabs, yes. However, it often happens that i want to change bigger chunks of the boundary curve, and using control point edit or vaSlabAdd/Subtract are impractical. I need to get the boundary of the slab, do my editing on it with all the Rhino curve modelling fancyness, then re-create the slab form the adapted curve.
To do so, 2 thing would be nice:
1 - Extract the slab boundary with one command (I’m using copy > explode > select srf > dupboundary > delete extra surfaces)
2 -Replace the slab’s boundary. There could be a curve picking icon in the properties, just like in vaElements: (might be in the wishlist already probably).

How to deal with holes in the slab… dunno yet. Just leave them?

Btw: Revit has a mode for editing slabs, where all curve tools are available. Closest to this is turning on edit points, but that has the aforementioned limitations.

Thanks a lot!
Best regards


Maybe you can do it more easily in Grasshopper using the Deconstruct Slab command and an automatic bake component (from Human, EleFront…)

Yes, it is already in the wishlist (Pick boundary curve after slab creation) but I’ll add this post so that there is more information to acheive a good result.


Thanks, Alfonso! Grasshopper, sure. As a workaround. It takes me a few (concentrated) seconds to punch aliases in the command line to get this. Maybe even quicker than fumbling it into GH. A nice little menu item in the RMB menu of the vaSlab would be more relaxed, though.

I like using this method, in top view run this macro:

Silhouette CurveBoolean DeleteInput=All CombineRegions=Yes Allregions Enter

NOTE: If you have holes in the slab you’ll need to select those, so depending on the complexity of your slab it might be more practical to ditch the AllRegions part and rather click within the slab after CombineRegions=Yes.