54471552-Creating-a-Hull-Lines-Plan-With-Rhino

Creating a Lines Plan with Rhinoceros 3D
by Dave Murrin (November 2007)
The following document describes a method for creating a lines plan using the commercial software
package Rhinoceros 3D. A rudimentary knowledge of ship terminology is assumed.
Rhinoceros 3D is a stand-alone, commercial NURBS-based modeling tool developed by Robert
McNeel & Associates. It is commonly used for Industrial design, Marine design, Automotive design,
CAD / CAM, and rapid prototyping. An evaluation version of the software (that is good for 25 saves)
can be downloaded from the Rhino3D website:
http://www.rhino3d.com/download.htm
Introduction
The process of developing a lines plan is not set in stone. For example, one student may find it easier to
start with a shear plan, while others find it easier to develop the lines from a series of sections. In the
end, the boat is a three-dimensional object and the lines represent the three-dimensional lines projected
onto an orthographic surface. The order is not important, since each of the lines define the shape of the
hull.
The lines plan consists of projections of the intersection of the hull with a series of mutually
perpendicular planes. The points of intersection of these planes with the hull are projected onto the
Body Plan, the Half-Breadth Plan, and the Sheer plan, as shown in Illustration 1.
(Source: www.nadn.navy.mil/NAOE/courses/en200/)
We will start this tutorial from the general shape of the plan deck and develop the hull in the following
sequence:
Part One
1. plan deck shape
2. profile of bow and hull bottom
3. sheer line
4. max beam line
Illustration 1: Boat lines

5. Rough Surface
Part Two: Lines plan
Part Three
1. Fairing the lines plan
2. lofting the surface
3. fairing the hull surface
Part Four: Hydrostatics
We will also be loosely basing our design on a canoe with the following specifications:
LWL = 5.0m BWL = 1.2m, Design draft = 0.15m, capacity = 190 kg.
Part One – The Rough Surface
Step 1: The plan deck
First create the centerline from 0,0,0 out to the right.
Use “curve > interpolate points to draw a shearline plan, as shown in Illustration 2
Turn edit points on (in the sidebar) and remove extra points. This smooths out the line. The line can
also be approximated using edit > rebuild, and selecting a fewer number of control points. Note that
this technique will be used later to fair the surface.
Note: for boats with a transom, this line should terminate at some distance away from the centerline,
and a separate transom line should be drawn.
Step 2
Change to the top view and lift the plan curve created in step 1 to some distance above the assumed
Illustration 2: The shear plan curve

waterline (i.e. the freeboard distance).
As shown in Illustration 3, use “curve > interpolate points” again to draw the bow and underbody
profile. Smooth the curves as before.
Optional step
Create the shear line profile view of the plan curve created in step 1.
Use “curve > curve from two objects” and select the plan and profile shear curves. This will interpolate
the deck edge. Delete the unwanted curves and keep the deck curve (see Illustration 4)
Illustration 3: Raised plan curve
Illustration 4: Shear line profile (optional)

The remainder of this tutorial assumes that the shear line profile view of the plan curve created in step
1 was horizontal. Illustration 5 Shows the finished shear plan.
Step 3
As shown in Illustration 6, create a rough hull shape at the maximum beam (and the transom if
required) and interpolate using “curve > interpolate points”
Illustration 5: Finished shear plan
Illustration 6: Maximum beam shape

Step 4.
Insert lines at the bow and stern, as shown in Illustration 7.
Step 5
Create a rough surface for the boat.
Select “surface > sweep along two rails”. Select the shear and hull bottom as the profile curves, and the
max beam, bow, and stern lines as the cross-section curves. As shown in Illustration 8, select the
number of control points to rebuild the grid (again, fewer is better), and preview the shape.
Now we have a rough hull shape to take our lines from.
Illustration 7: Midship section curve
Illustration 8: Rough surface