I've been tracing out a background CAD mesh with Line tool (normally using a combination of Line and Spline).

When I hit the Curves to Surface to convert the shape to a polygon, half the time nothing is made and my drawn curves are gone. I used to think I didn't connect lines enough, but I have my Snap Panel set to only Points.

I've seen this happen on both my Mac & Win machine in LW2018 & 2015.

Anyone else have this problem?

The Next beta will be out very soon.
It has a new Flat Patch tool, specially designed to create patches from the floor-plan.
It is also running on the new MeshTR engine which is working with the new bug database.

So every time some special case is reported, it is stored into DB, and checked automatically before each new release.
Tools with this system will be soon practically flawless.

Whenever you find some simple floor-plan that doesn't work, please send it via support bug report. It will help to get the Flat Patch tool matured sooner.

Thanks. I'm assuming that the Arc tool might get fixed too.
Sometimes that just goes wild and unpredictable.