Orient Curve to Edge

Hi everyone,

I am learning Rhino Level 2 and it’s going great. I need explanation of a command if you will.

I am on Exercise 21: Creating a crease. There is a command called Orient Curve to Edge.

Can you explain to me what is exactly being oriented? When I run the command a line appears to be orienting perpendicular to the edge. Is that correct? What is actually being oriented? Excuse my nontechnical language but are normals being oriented? Is it oriented perpendicularly? What is happening?

Thank you.

Hi, Here you have some information about it.
http://docs.mcneel.com.s3.amazonaws.com/rhino/6/help/en-us/commands/orientcrvtoedge.htm

If the curve already starts on the edge, it is copied to a new location on the edge with the same orientation as the original curve had to the surface.
If the curve does not start on the edge, it is rotated so the picked end of the curve is tangent to the surface and perpendicular to the edge.
If the curve tangent at the picked location is in the same direction as the active view's construction plane, the curve is not re-oriented to be tangent with the surface.

Thank you. I didn’t see this description.