Thought to Hydro to Cad to Paper and Beyond.

Lp here is the same file in rhino, I saved it in a rhino 2 format, there are some more rhino files of hulls scattered through this thread, http://www.boatdesign.net/forums/design-software/hull-files-anyone-26361.html If you want to try some others.

 

Eric, I'm curious why you use polylines in 2D drawings rather than splines. Do splines still cause difficulties with some "professional" CAD software?

 

I just find working with polylines a lot easier. I can turn a polyline into a spline, or I can draw a spline directly. For example, if I want to draw the outline of a rudder aerofoil section to very precise offsets in AutoCad (where I have NOT created the surface model of the rudder in the hull model--I typically don't with rudders), I first input the offsets directly where they go into a little X-Y grid, and then I draw a polyline through those points, snapping to each one. Although this gives me a knuckled shape for the line, it also gives me enough control points to work with to edit the line. I usually put in one or two extras points near the leading edge where the curvature is tighter. Then I convert the polyline to a spline, and now all the input points on the knuckled polyline become spline control points. I then begin at one end pulling the control points out so that the spline line goes right through the original offset points. I work back and forth from TE to LE until the spline sits on all the offset points, and I get a proper aerofoil outline. If I am working in ProSurf, I can create the spline immediately by entering basic dimensions, but that involves creating new files in different formats and importing them into AutoCad. It is just a lot quicker to work in AutoCad directly.

In my 3D hull models, of course, all the surface control curves are B-splines which lie one the surface. They are not way out in space as is typical with a lot of hull design packages. So I can manipulate the shape of the surface by pulling directly on the surface--it is extremely easy. Once I've created the hull shape to my liking, I don't need to manipulate the surface splines anymore, and so I don't export them into AutoCad. They would be 3D lines anyway, and I don't draft in AutoCad in 3D. Rather, I specify cuts through the hull to give me traces of frames, girders, waterlines, etc, whatever I want. Then I export those lines in 2D orthogonal views to AutoCad as polylines. I can edit them just fine from there--cut them short, add to them, move them around, and offset them up, down or sideways.

Eric