Filleting parallel lines gets message "cannot fillet between these two entities" parallel lines

[swatfor_PDCOG]

I offset a 2d polyline and then try to use the fillet command to add an arc between the two lines. I receive this message "cannot fillet between these two entities."

I am using Civil 3D 2021 and trim mode is set to trim. The lines are parallel and in the same plane.

What am I missing?

[swatfor_PDCOG]

added this here because the original post would not accept this URL to the screencast showing the pr...

https://autode.sk/3jsinOC

[user181]

You can fillet parallel lines that way but it doesn't work with polylines. I not sure why but it doesn't. 

[Kent1Cooper]

Help says that works only with Lines, Rays & Xlines.

If you want to do it with Polylines, you can use my CapEnd.lsp routine with its CE command, available >here<.  Choose the Arc option.  In the case of your example [both Polylines and on the same Layer], it will even Join them and the new Arc into one Polyline.

[pendean · Accepted solution]

From HELP

pendean_0-1625005580813.png

[Erense]

All true but if it is a polyline and the form is like the example from @pendean you can use the 'close' function for the polyline and then change the segment to an arc. It's kind of extra work but it can be done:

Polyline fillet.png

[swatfor_PDCOG]

Thanks for the quick solutions.  I appreciate it.

Sandy W.

[Jordan_Warner6M2QQ]

@Kent1Cooper This LISP is great, thanks for sharing. Much better than polyline "close" and then trying to eyeball a tangent!