Can't extrude polyline

Žiga Lausegger

Hello, 

I have drawn a rectangle and extruded it. Then I turned on UCS and started drawing a polyline on the top face of extruded rectangle. I selected all the polylines and used /modify/join command to create one big closed polyline. But when I try to extrude this nothing will work.

Where did I go wrong or what do I still ned to do in order to extrude this closed polyline? 

Thanks.  

Roy Klein Gebbinck

Without a dwg I can only guess: Non-planar 3D polyline?

Žiga Lausegger

 Oh ok I will add the .dwg (attachment) and a printscreen of the problem: 

nosilec-aluminij-30x30.dwg

Roy Klein Gebbinck

Your 3D polyline is indeed non-planar. For vertex 5-11 the Z is 1.93670000. For other vertices the Z is different. For vertex 1 it is 1.93669962. Since you seem to want arc segments using a LWPOLYLINE (as you do in the four corners) makes more sense than a 3D polyline. And with a LWPOLYLINE this problem would not have occurred anyway. You can use the _FLATTEN command (I had to switch to WCS and switch the PLAN to 'world' as well to get the desired results) and then move the polyline back to the correct face.

Žiga Lausegger

Thank you. This was helpful. Is there any way to create an UCS on a top plane and flaten on that plane?

Roy Klein Gebbinck

Apparently this is not possible. I was surprised by this as well. What I find even stranger is that the FLATTEN command uses the view direction instead of the Z axis of the current UCS to project the entity. Since the view direction can be pretty random this leads to unpredictable results.