Just want to create a 3d geometry line automatically (NOT BEST FIT)

If you are using the OpenRoad Geometry tools, you cannot really draw 3D graphics like it seem you are trying to.  You seem to be using the Horizontal Line tool to draw in the 3D model.  ORD is going to let you do that but will create the geometry in the 2D model and create the 3D according to the create 3D automatically which does appear to be as you mention the Best Fit.  If you use a MircroStation "Place Smart Line" you can draw a 3D line in the 3D model.  Then use the "Place Plan By 3D" tool in the Model Details ribbon 3D Tools Group.  This will create 2D plan elements with the Feature Definition you select as well as a Profile set to match the 3D line string.  I think that will get you what you are looking for.

If you are using the OpenRoad Geometry tools, you cannot really draw 3D graphics like it seem you are trying to.  You seem to be using the Horizontal Line tool to draw in the 3D model.  ORD is going to let you do that but will create the geometry in the 2D model and create the 3D according to the create 3D automatically which does appear to be as you mention the Best Fit.  If you use a MircroStation "Place Smart Line" you can draw a 3D line in the 3D model.  Then use the "Place Plan By 3D" tool in the Model Details ribbon 3D Tools Group.  This will create 2D plan elements with the Feature Definition you select as well as a Profile set to match the 3D line string.  I think that will get you what you are looking for.

Thank you, sounds good, will try it tomorrow. Can always count on DOT guys for support!