Hi Petr,

> Could it these alternatives be driven by "Project to plane in
> ortho view" option?

Maybe... But to be similar to a constraint-based modeler it kind of seems like this particular function should always be relative to a plane.


> I rarely want to change all three base point's coordinates of
> object at the same time while running a move command so I
> think it should place final point on the base point's elevation there.

Yeah, I think that makes the most sense and is the most consistent with other functions, like if you draw a line in an ortho view (with that default project option on) the elevation is set by the first point you pick.

There is one additional factor yet, which is that the line may be angled diagonally upward instead of being parallel to the construction plane.

So to handle this different elevation type problem, I'll get a construction plane with the base point's elevation, then project the line on to that plane and then find the distance to that projected line.


> I guess the final point inherits the elevation of base point in
> case of 3D distance measurement in current implementation(?)

It was along a vector between the base point and the point projected on to the line. So it could have been kind of traveling diagonally in 3D and not on either elevation... But now I have it set up so it will use the base point's elevation.

- Michael