Like Autocad, In ZWCAD+, the Extend command can extend the specified objects to meet the specified edge.(ZWCAD, CAD Software from ZWsoft)
Button: extend Objects
Ribbon: Home » Modify » Extend
Keyboard: extend, execute Extend command
Select objects or < select all >: select one or more objects and press Enter, or press Enter to select all displayed objects.
Select objects to extend.
Select objects or < select all >: selected 1 object, 2 objects in all
Display the number of the objects you select.
Select objects or < select all >: press Enter or the right mouse button
End selection, or go on selecting more objects.
Select objects to extend or shift-select to trim or [Fence/Crossing/Project/Edge/Undo]: select objects to extend, or hold down SHIFT and select an object to trim, or enter an option.
Select objects to extend, end extension, e.g. picture 1.
Picture 1: extend objects
Fence: Select all objects that cross the selection fence.
Crossing: selects objects within and crossing a rectangular area defined by two points.
Project: specifies the projection method used when extending objects.
Edge: extends the object to another object’s implied edge, or only to an object that actually intersects it in 3D space.
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More information: How to set up drawing units in AUTOCAD