The splitting boundary drawn would result in a self-intersection of the surface

[Anonymous]

Hello,
I have drawn and modeled a toposurface for hours. I already applied the command split region to cut a part and delete it, however it seems like the command doesn't work anymore on this toposurface whatever I try to do. (Note: the toposurface contains subregions that don't intersect the split region i want to create)
Now:
- I have not drawn a non-closed loop (Even if I try with a circle it shoes me the error..)
-The sketch is not out of the toposurface's projection
-I tried to delete the subregion but no luck
-I tried to restart revit but not luck
-I tried to copy/paste the toposurface on another new project but it doesn't work
- If i draw and model another simple toposurface the command does work.

It looks like the toposurface has got something that doesn't allow the commant ''split region'' to work anymore and I want to know why, I can't waist hours of work and the handing in is imminent, thanks for the replies

[barthbradley · Accepted solution]

You did something that Revit can't reconcile. It's happened to me. If it's so messed up that you can't delete a Sub-Region, I'd throw in the towel.  

[Anonymous]

Suggest using roofs for your roads vs subregions after you rebuild or grab a backup.  Also keep a backup of your topography in an earlier phase and demo'd so you can get it again if you mess up something...(or a separate file)

[ToanDN]

You can:

- draw a building pad in lieu of split surface to cut a hole in the topo

- create a subregion and hide it by a means of your choice

[Anonymous]

Maybe I didn't explain well that I don't really need the subregions, I only pointed out that there's a subregion in case someone came up with ''try to delete the subregions''. I can delete them but that's not the point. I use split region a lot to cut out parts and eventually attach the topography to walls/floors with alignment for the sake of having a clean joining of the model with the toposurface. My goal here was to create several split regions and delete them but it looks like, how you said, that revit couldn't just reconcile with this one. Looks like a bug. I even tried to simplify the whole topografy into 4 points but it still wouldn't let me cut it ... Something went very wrong with this topography
I gave it up and redrawn the entire topography, now I can cut it as much as i want, thanks for the replies