UCS position changing using Pedit

Tim Neumann

Don't know if this is the way it's supposed to be or not. When working in 3D and trying to join lines and arcs to form an enclosed entity for extrusion the UCS will change position after typing yes to the pline question (using Pedit command). This doesn't happen all the time and won't occur when picking arcs but I don't know yet what the pattern is. Tried making sure elev is 0 but that has no effect. Anyone know what's going on here? This is for V12.7.1 thanks!

Roy Klein Gebbinck

Planar entities such as arcs and 2D polylines have a normal vector (also known as the extrusion direction). If that direction does not match the Z-direction of the current UCS, the Pedit command will change the UCS so that it will (this also happens with arcs by the way). I don't know if this is done to help the user or if this is required for some other reason.

What is peculiar is that lines, which are not planar, also have an extrusion. If you try to join three lines that form a closed triangle in 3D space, Pedit can assign a new extrusion to the first line you pick (based on the original extrusion and the direction of the line) that does not match the normal of the plane described by the three lines, making it effectively impossible to join the lines. Matching the UCS to the plane of the three lines (using the 3P option) does not solve this.

But I do not have a lot of 3D experience so I may be missing something obvious here.

Knut Hohenberg

No, it is not supposed to be like that. I noticed this on one of the first betas for linux quite a while ago, but was too lazy to report it.
The problem is as follows: if you create lines that do not lie in the active ucs plane, the entity coordinate system still is the current ucs. If you then align the ucs to some of those lines and try to join them, pedit will fail, since it regards the lines as not coplanar with the current ucs. I'll take the time and file an SR now...
At the moment, I know of no other solution than to align the ucs first, and then create the entities to be joined.

Knut Hohenberg

Sorry, Roy, you were faster than me - did you perhaps already file a SR, so I won't do it?

Tim Neumann

Something I forgot to add was after joining all entities and completing the pedit command, the UCS does revert back to previous location/orientation. I guess it's like Roy says - make sure you have the Z plane lined up with the direction of extrusion. It's really not that big of a deal except it being a little bit distracting. Thanks for the feedback.

Jason Bourhill

Hi Tim,

Try using REGION instead of PEDIT. Region allows you to select lines and arcs to form a closed region, which you can then extrude to form a solid. It's actually quicker than using PEDIT.

Of course PEDIT should work

Regards,

Jason Bourhill

CAD Concepts

Knut Hohenberg

I actually had a closed SR for a similar case (32266), which was a regression in V12 that has apparently been fixed.
So probably this problem will be gone with the next release...

Roy Klein Gebbinck

@ Knut:
The Pedit problem with lines in 3D space exists in V10-V12 so your SR must refer to a different issue. I'll file a SR for this one.

Knut Hohenberg

@Roy
OK, do so - I just have V11 and V12 beta on linux installed, and - while I remember it in V10 - the problem was gone in V11 and back in V12 beta...
I did also upgrade my closed SR yesterday and asked whether this problem would be covered by the fix already implemented.

Tim Neumann

@Jason

Thanks for the Region tip, it worked perfectly!