Yacht design in Rhinoceros 4

[Joe Petrich]

You can create hulls in Rhino several different ways: reshaping one surface, lofting through section curves, sweep 2 rails for chined vessels, etc. the key is to use as few control points as necessary to get the desired shape. More control points = more chances of unfair curves or surfaces. This is true for some other hull design programs as well.

[marshmat]

Keep control points to a minimum, always. Never use a 10-by-10 surface to create a shape that only needs a 5-by-5. The latter is four times easier to tweak while keeping fair. Use the CurvatureGraph tool, with the surface isocurve density cranked up, when cleaning up hull surfaces; it's far better at finding unfair spots than humans are.

A few other things I've found handy that haven't been mentioned yet:

Rhino4's "record history" feature is remarkably useful for yachts. It's ideal for mirroring the hull on the centreline, of course, but has other benefits. For example: Create the cutplanes for the (stations/buttocks/waterlines/diagonals), on their own layer. Group them. Switch to the layer you want the curves to appear on. Turn on history, intersect the cutplane group with the hull surface, turn off history. Hide the cutplanes layer and lock the curves layer. The intersection curves will now update in near real time as you nudge control points on the hull surface, and won't get in the way.

If you already have an approximate 2D linesplan, dragging those curves out to their appropriate 3D positions lets you easily compare the 3D surface and intersection curves to the original linesplan.

A 3DConnexion controller ($60) is more than worth it. Once you've used this thing to fly through your model and instantly get *exactly* the 3D view you're looking for, without disrupting the operation in progress, you'll never understand how you got along without it.

[bhnautika]

Here is a slightly different but similar method to marshmat’s. Create a single plane through your surface; turn on the history and do the intersection line as before (at this point I change its colour to make it stand out more, I also turn off the surface isocurves for the plane in the properties box to reduce line clutter).Select the plane surface, now in either plan or profile view, holding down the shift key you can drag the plane surface up and down the other surface and have the intersection line go with it so you can position where the control points are for editing. Also if you turn on the curvature graph for the intersection line it also changes with the movement of the intersection line. Those with rhino 4 see file.

[pavel915]

I am really impressed by the dynamic sectioning trick as mentioned by Marshmat and bhnautika... thanks a lot for sharing those tricks...