How to make a 'offset' without changing the vertices of a curve 'polyline'

When I use the 'offset' command in the curve line, the parallel line created has its vertices with the spacing becoming each time larger than the original line. In some cases the spacing is not greater, but the configuration of the vertices has changes.

Is there any command or some form of performing the 'offset' without changing the configuration of the original line vertices?

Welcome to CADTutor.

Try the COPY command instead, and they will never change.

If you OFFSET an arc to the inside the spacing becomes smaller, in proportion to the radius, that is just the nature of the beast we lovingly call geometry.

Offset makes a parallel object to the offset object. The radius of the arc changes when offsetting an arc to remain parallel, therefore the vertices must move. The vertices must occur on a radial line from the center point of the arc radius to the ends of the arc. Like Dadgad says, it's sixth grade geometry.

Copying an arc does not change the radius of the arc, but it does not result in parallel arcs at all.

Very succinctly stated Dana.

Does Autocad 2015 have a DEFYEUCLID command?