Section plane doesn't work on a spiral staircase

[Anonymous]

Hello everyone, I'm working on Autocad 2018 for Mac (OS Mojave 10.14.5) and I'm currently assembling the 3D model of a building, that I'll later need to section in half and 3D print.

There are some spiral staircases (created as an intersection between the single steps and a sweep along a helix) that seem to create troubles. Namely, when I place a SECTIONPLANE in the desired position, and activate the live sectioning, everything gets sliced except for the stairs (see picture).

Staircase in cyan, bottom right

What's even stranger is that, just a few hours ago - before adding parts and details to the structure - I've sectioned that very stair and no problems appeared.

It is not an array, nor a block... I honestly have no idea what the issue could be.

The other issue comes with two smaller stairs, not visible in this screenshot, which are impossible to merge to the rest even though they intersect in more than one point.

Has anyone had similar problems? 

Thank you in advance for you help!

Alvise from Italy

[injineri]

maybe its some kind of group or block and section not working on it. try to EXPLODE it and after that SECTION

[Alfred.NESWADBA]

Hi,

>> before adding parts and details to the structure -

>> I've sectioned that very stair and no problems appeared.

And when you remove these parts, does SECTIONPLANE work well again?

>> It is not an array, nor a block

So which types of geometry are these new parts?

Any chance you upload the dwg-file and describe the layers of these objects that were added?

- alfred -

[andkal]

What type of object is it (the stairs) ? If it was AEC_STAIRS you may have accidentally exploded it into a block.
Paste this code in command line and pick stairs to check this objects type.
(cdr (assoc 0 (entget (car(entsel))) ) )

[Anonymous]

Hello everyone and sorry for my absence. Last week I redesigned the stairs and sectionplane worked just fine. But then again, after a while the issue appeared back. Foreseeing this might happen, I had created a backup file with the stairs only: guess what, even that doesn't seem to work.

I checked again and there is no block, group or anything. I'll leave here the two files for you to check, maybe the issue appears on Macs only? (I've tried it on mine and on my friend's Macbooks, but not on Window yet).