Surface normals different while editing blocks

This is my first post, although I’m a long-time Rhino user.

In my office, we use blocks quite a bit. For the first time today, I have a behavior that has never happened to me before. My typical working view settings have a single color for the backfaces, so I can make sure all the normals are correct. While I’m zooming around the model, everything looks fine. Then I edit a block, still fine. Then I finish editing the block and… the normals are all flipped! Edit the block again, the normals are correct, exit, and they are all flipped.

Anybody encountered this issue? Any help would be greatly appreciated.

Hi Damon,

I’m not seeing this here editing a block that is either created and then edited in a single file or inserted from another. Can you share a sample model that shows what you’re seeing? Please add notes to the file or give any other information as to the steps you go through if possible.

Hi, Brian. This is Damon from Safdie Architects. I was on a hiatus from Rhino, working in Revit, but I’m back and see that you upgraded the forum. It’s great! Below is a better description than yesterday.

Correct normals, outside block editor:

Reversed normals, inside block editor:

All I did was double-click on the block to start editing it. Here’s just the block I’m showing, and for me it still does the same thing:
normals2.3dm(211.7 KB)

Hi Damon,

Thanks for sending the file. That is really odd! If I explode the block and then block the objects again it doesn’t happen. Was this geometry native to Rhino before the blocking? I’ll file this now for development to look into but please add any further information here if something comes up.

Filed as RH-20775, this report is not publicly visible at this time.

Yes, I think it was created native to Rhino. Very strange indeed. Thanks for the response.

RH-20775 is fixed in the latest Service Release Candidate