miauu’s Polyline allows you to create splines precisely with measurements and angles.
Now precision spline modeilng is easy and faster.

Create splines using:
– Ortho mode – it constrains drawn lines to the horizontal or the vertical
– Polar Mode – it constrain your cursor movement into predefined angles
– Freehand mode – create points without any constraints
– Arc mode – create an arc that is a part of the current spline
– Object snap tracking – mark certain points on your geometry(splines, mesh objects, grid points) and continue to draw in their projection or intersection points.

Not tested.