SEO - intersect not working

[Patrick M]

I have an issue where I am trying to solid element operate - intersect a slab to a topo. When the slab is set as the target, and the mesh is the operator, the operation is intersect, the slab disappears, rather than conforms to the mesh as it should.

The video shows what I'm dealing with. Anything other than layers, renovation, design options, building materials, session report errors... that I should be checking? This is replicated in a .mod opened or copied into a new file. The original site is more complicated, but eye dropping it and placing a new one replicated the issue (as seen in the short clip):

https://youtu.be/NjE8_Jtaa0Q

Screen shots for those who don't want to view the clip...

   Also worth noting, if I try to open the .mod in AC30 and select any element, it crashes... 

Operating system used: Mac Apple Silicon

[Patrick M · Accepted solution]

disregard... mesh was not solid. Thanks @JaredBanks for the quick solution that I've been wasting so much time hunting for! 

[JaredBanks]

Happy to help. Worth noting for everyone else following along, if you're using two Meshes (rather than a Mesh and a Slab, which is the correct way to do this technique), then both need to be set to Solid Body (third icon).

For more on this technique of double SEO for cutting roads into site meshes: https://www.youtube.com/watch?v=PuqtMqV6RuY&t=310s