Modeling a Sailboat

This tutorial details every step of building the boat model pictured above. Because this boat is a serious, professional project, it probably should not be the first tutorial you follow in learning Rhinoceros, and it does assume at least a basic familiarity with the Rhinoceros interface. Please allow at least two days to complete this tutorial. In addition to following all the steps, be sure to check out the optional pages - they describe other solutions to many of the issues raised in this tutorial, and even cover how the scene above was textured, lit, and rendered in Rhinoceros.

On the CD-ROM, you'll find several .3dm files in the boat directory that the tutorial will tell you to load at appropriate times, including templates, reference images, and annotation. There is also a final copy of the scene pictured above, along with several partially-assembled stages of the project against which you can check your work. All texture maps used in the rendering above are also included, in the materials subdirectory.

1 Modeling a Sailboat: Hull / Background Images

Open boat1.3dm and save it out as boat.3dm on your local hard drive in a new subdirectory called boat.

Optional: To match your colors to the figures in this tutorial, call up Tools/Options... and click the Appearance tab. In the Colors section, click on the color swatch to the right of the words "Viewport background," and the Rhinoceros color picker window will open. Click on the Named Color labeled Dark Gray, and click OK.

Still working under the Appearance tab, click on the "Major grid line" swatch. In the color picker window, enter a Hue of 0, Sat of 0, and Val of 80, and click OK. Repeat to set the "Minor grid line" to the same color. Click OK to exit Options.

Click in the front view, and choose View/Zoom/Extents.

To bring in an image to sketch over, go to View/Background bitmap/Place and when prompted, locate the file boat/Background/sections.tga on the CD-ROM.

Turn on the osnap 'End.' Working in the Front window, click once in the upper left corner of the rectangle, and then click again in the bottom right of the rectangle. This will align the imported image with the spline guide, so that the boat you build will be at the same scale and position as the sample files on the CD-ROM.

After the second mouse-click, a dim gray figure will load into the background, as shown below.

Maximize the front view and study the blueprint that you have imported. The views of a model shown in blueprints are often drawn differently than the views in Rhinoceros modeling windows. The scanned-in blueprint shown in the Front view actually depicts more than one view in the same model: it shows the boat from the side, with curves from the front and rear views superimposed near the center. This one blueprint image will provide many of the design specifications required to model the boat. Note that no blueprint is ever perfect, and that your own creativity as a modeler will come in to play at several points during this tutorial.

In the layer control window, turn on layer annotate1.

The numbers 1-10 point to the top end of each of an important set of curves. These 10 curves are the "sections curves" of the blueprint. The section curves are the main curves that will be used later to loft the hull.

The section curves on the right (1-4) form the bow (the front end) and the sections on the left (5-10) form the rear of the boat.

Turn off the annotate1 layer. With end osnap off, trace over the lines 1-10 using InterpCrv (Curve/freeform/Interpolate Points). Note in the figure below that the curves being drawn can exceed the length of the section curves shown in the blueprint. These will be accurately trimmed off later.

Also note that lines 5 and 6 are similar in position, and may appear to be almost the same line. Carefully trace both of them.

In addition to the 10 numbered section curves, also draw a "centerline" straight down the middle, as shown below.

Save your file when done drawing all 11 curves.

2 Modeling a Sailboat: Hull shape

NOTE: The following steps will rotate all the curves to the same side of the boat, in order to distribute them down the length of the hull and prepare for a loft command that will surface the hull.

Select the 6 curves that form the rear of the boat, shown selected below. Turn on the 'end' osnap. With the perspective view active, hit Rotate3d (Transform/Rotate3d), select the top and bottom of the centerline, and enter -90 degrees. In the front, view drag the curves to your left by 2 grid squares.

NOTE: This will prevent them from overlapping with the front curves, which you need to rotate them around. Select the other curves, which represent the front of the boat, and rotate them by (positive) 90 degrees. Result shown below.

Save your file and continue with the curves you have (or open boat2.3dm)

Maximize the front view and turn on layer 'divide'.

Draw a curve from 10 to 0, which is the approximate length of the hull. Select the curve and use the divide command curve/point/divide curve by/number of segments. Enter 10 when prompted for 'Number of segments'. This puts 9 points evenly spaced down the length of the hull.

In the perspective view, select the curve marked (1) below. Switch to the front view, hold down the Shift key (temporarily activating 'ortho' mode), and drag the curve horizontally to position it underneath the point labelled (1) below. NOTE: If you need to check your work at this point, turn on the layer named 'sample'.

Continue distributing the remaining curves by moving each curve into alignment below its correspondingly numbered point, as shown below, and your results should resemble the image below..

Don't forget that you have two lines close to, or on top of, each other at section 5 and 6. Delete 'sample' layer as well the annotate layers if you don't need them.

3 ，Modeling a Sailboat: Hull shape

Save your file, and merge the b3.3dm file into your scene, or open boat3.3dm for a complete version.

The red line in the image above indicates the object, line or curve that we are focusing on. With the front view maximized, and with end osnap on, draw a curve InterpCrv (Curve/freeform/interpolate points) from 1 to 2, tracing over the bow stem background line shown below.

Start another line from the end of the last line (2) and go to (3) and end the curve, repeat from 3 to 4 and 4 to back to 1. The image below shows the first curve drawn.

Use the top and bottom curves to trim off the tops and bottoms of the hull curves. The two curves to the left (9 and 10) do not need to be trimmed.
Note: If the section curves don't cross the outline curves, select the section curve and turn on the control points using PtOn (Edit/Point Editing/Control Points On). Now select the top CV and move it over the trim line, as shown below.

Delete the second to last curve (9). We don't need that curve, but we do need to make the last curve (10) angled to match the back end of the boat (transom or stern as it's called) which we will cover on the next page. Turn on the 'annotate curve numbers' layer to see the curve number if necessary.

Select the line (stern line that goes from 3 to 4) in the front view. Hit Extend, and when prompted 'Select Boundary Objects,' hit Enter (or spacebar.) When prompted to 'Select object to Extend,' select the curve and drag the end of the curve outwards, or enter 30 to numerically control the extension.

Hit Extrude (Surface/Extrude/Straight), and with the 'BothSides' option activated, extrude the new plane wider than any of the curves in the right view.

Create a new layer, call it 'Transom,' and ChangeLayer the extrusion to that layer.

Go to the left view and select the curve and project Proj (Curve/from objects/Project) it onto the plane and hide the 'Transom' layer and save the file.

4 Modeling a Sailboat: Hull shape

Save your file or open boat4.3dm

Select the bow curve (the curve highlighted below)

Rebuild (Curve/Edit_Tools/Rebuild) the bow curve with 12 points.

With the bow curve still selected, from the right view drag it to the left one snap (or -2.5 units.)

Overview: we need to keep the bottom and front edge of the hull 2.5 units away from the centerline to allow for the backbone of the boat to go down the center of the boat. This will be gone into in greater detail on Page 7.

From the right view, select the station curves and Rebuild them (using Curve/Edit_Tools/Rebuild) with 12 points. Select the station curves (1 through 10 below) and show CV's PtsOn (edit/point editing/Control Points On).

You now have the basic curves that you will need in order to shape the hull. However, they still need to be "tuned up" before they can be lofted to create a smooth hull surface.

5 Modeling a Sailboat: Hull shape

Select the bottom two control points of each of the section curves shown below, and the bottom 5 of the transom curve, using Lasso. From the left view, turn on grid snap 's', and hit SetPt (with only Y checked off), then drag the points by -2.5.

Check out the top view and notice how the ends of the curves are not lining up with the middle of the background image rail (indicated by the red line below). To get a better visual reference turn the 'End' osnap on, and draw a InterpCrv connecting the top ends of the 'section' curves with a curve going the length of the boat.

In the top view, select any curve that does not go all the way to the red line above, which marks a location in the middle of the rail. Scale1D the curves into place, being sure to snap the 'Origin point' to the end that is closest to the center line.

At this point you can continue with the tutorial or read the Optional Notes about 'visualizing the hull' surface and curves to check for errors.

Optional Notes ：
http://www.3drender.com/rhino/boathtml/Opt_1.htm

6 Modeling a Sailboat: Hull shape

NOTE: Building the hull is the hardest part of building a boat or ship. You've been working since the beginning of this tutorial preparing for this Loft operation - now here's the big "payoff!"

Select all the section curves, including the bow, and hit Loft. Use a normal Loft, with 'Rebuild with 12 control points,' hit OK.

Well, check it out, to me it doesn't look too hot because there are shadows that indicate a uneven surface so let's give it the RebuildSrf treatment. Select the surface and hit RebuildSrf and make the settings 8 U and 8 V.

Congratulations - you've just completed the most difficult part of this tutorial. In the next section, we will finish the hull and add a deck and details.

7 Modeling a Sailboat: Backbone

Save your file and merge the b5.3dm file or open boat5.3dm

Together, the bow stem, the keel, and the stern post, shown above in red, form something like a "backbone" for the boat. The backbone area is a 5 unit wide center piece from the top view, and basically holds the boat sides and stern together. (Backbone is not technically a boat term, but it is a useful description. The timber used to make these three parts are also referred to as deadwood.)

Hit SelCrv and delete all of the curves, or make a layer and ChangeLayer the curves into the new layer. Finally, hide the hull surface.

Trace over the backbone (shown as a red line in the image below) referencing the arrows on the layer 'annotate3'. There is also a sample curve to use (or just to inspect for reference) on layer 'keel sample'.

Use InterpCrv to trace over the background image curve indicated in blue below . This is just a temporary deck curve to be used for alignment in building the backbone.

Hit Show to show the hull.
8 Modeling a Sailboat: Backbone

On this page, the hull edges and deck will provide the curves needed to finish the "backbone."

Duplicate the edges Dupedge (Curve/From Objects/Duplicate Edge) of the hull, as shown below.

From the front view, project the dupedge curves to the construct plane ProjCp (Transform/Project to CPlane). This will put all the curves needed on the construction plane.

The following steps will show how to trim the curves:

Select and Hide the hull using Edit/Visibility/Hide.

Hit Trim, select the deck curve as the cutting object, and trim off the pieces indicated by the arrows below.

9 Modeling a Sailboat: Backbone

Hit Trim again, select the outside backbone curve shown highlighted below, and select the center part of the deck curve for when prompted for the curve to trim. The figures below shows that two "tails" are left at each end of the deck curve.

Hit Trim again. This time, select the two curves shown below as the cutting objects, and then trim off the ends indicated by the arrows.

10 Modeling a Sailboat: Backbone
You should now have the curves highlighted below:

In the front view, select the new curves, and hit Join. Select the joined curve and hit Extrude 'Cap=Yes' type 'c' to select the cap option, 'b' to activate the 'BothSides' option, and finally enter 2.5 as the 'Distance'.

Note: If you don't see a cap option, it means that the original rudder curves you made did not snap to each other's ends to form a enclosed area. Check the curve corners to see if they meet exactly end to end.

That completes the backbone of the boat.

11 Modeling a Sailboat: Finish up the hull
Save your file, and merge the b6.3dm file or open boat6.3dm

The 'transom' is the rear panel of the boat, shown in white below. The red line below indicates an important curve that forms the top of the transom, running from one side of the hull to the other.

In the right view, select the point shown below and drag it about 5 units to the left. The hull is now prepared for a mirror operation.

From the right view, select the hull, hit Mirror, and enter '0'. Hold down the Shift key (to temporarily activate Ortho), move your cursor straight upwards, and click to define the end point of the axis of reflection. The mirrored result is shown below.

12， Modeling a Sailboat: Finish up the hull
Turn on the layer annotate4, turn on the 'End' osnap, and turn on 'Planar'. Use the InterpCrv command to draw a 3 point curve between the points labelled (1) and (2) below. Position the middle point on the center axis, slightly above the height of the end points.

Turn on the transom layer. From the right view, Project (Curves/From Objects/Project) the curve you just drew onto the plane from the transom layer. Hide the transom layer.

Select the source curve from the previous projection and ChangeLayer it to the transom layer.

Hide the Keel, and draw a curve between the points labelled (3) and (4) below, to connect the the bottom of the hull sections.

Hit EdgeSrf (Surface/Edge Curves), and select the four curves that make the transom as shown below.

The hull is now complete.