With F1 Entity off draw a line beyond your arc and Pick to the side opposite
Now pick the line(s) you want to extend.
Then use FreeTrim (in the CleanUp menu) select the arc, click on Begin
Click on the line you extended on the part you do not need.
This actually goes much faster than it reads or types. The ability to extend to an arc would be a very useful addition though. One for the Wishlist I think.
Hope this helps.
AJ Blasio (aka Tony)
DataCAD 18 (DataCAD User since v5) Windows 10 Intel CORE i5 8GB Ram
Like I said earlier, the ability to extend or 1-Line Trim to an arc would be a great enhancement. However, I am so used to not having it that the workaround is not a big deal.
Maybe Dave G. at DataCAD can let us know if this is possible or maybe even a v12 enhancement.
AJ Blasio (aka Tony)
DataCAD 18 (DataCAD User since v5) Windows 10 Intel CORE i5 8GB Ram