# Maxsurf Tutorial3-Chine hull using multiple bonded surfaces

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Tutorial 3: Chine hull using multiple bonded surfaces
1.       If you have an existing design open, you will have to close it
first (File | Close Design). Select File | New Design menu option.

2.     Create a topsides surface from a flat, longitudinal plane
(Surfaces | Add Surface | Longitudinal Plane).

3.      Size the surface using the Surfaces | Size Surfaces command.
Set the Length to 40 m and the Depth to 3 m. Save the design using
the File | Save Design As option. The surface should look like this in
the perspective window:

4.     In the Profile window add 3 control point columns using the
Controls | Add Column command, to bring the total number of control
point columns to 5.

5.      Go to the Surfaces window and rename the surface Topsides
and change the longitudinal flexibility to 4 (one less than the number
of control point columns)..

5m (to the beam of the hull) using the Surfaces | Move Surfaces |
Numerical menu option. Select the Topsides surface and set the
Transverse distance to 5m and the Longitudinal and Vertical distances
to 0m, click OK to close the dialog box:

7.      In the Perspective window, select the fwd two control points
and select Control | Control Properties from the menu. In the dialog
set the Offset value to 0m, this will close the bow of the topsides:

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8.      To create a chine surface which can bond with the lower edge
of the topside surface we must create a surface with the same number
of control points along the bonding edge as well as the same
longitudinal stiffness. The easiest way to do this is to make a
duplicate of the topsides surface. Select Surfaces | Duplicate Surfaces
from the menu. A Duplicate Surface dialog box will appear, select
the Topsides surface, enter 1 in the duplicate edit box and set the
vertical spacing edit box to –3.5m. Rename the duplicate surface
Chine:

9.     Transfer to the Profile window to Bond the surfaces. We want
to bond the top edge of the Chine surface to the bottom edge of the
Topsides Surface. To do this select a control point on the bottom
edge of the Topsides surface (any point except a corner point) and the
corresponding point on the top edge of the Chine surface. Select
Controls | Bond Edges | No Tangency, the two bonded surfaces
should now appear similar to the following:

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10.     Select the bottom row of control points on the Chine surface
with a box. Select Control | Control Properties from the Menu and set
the Offset positions to 0m and Height to –1.5m. Switch to the Plan
window and move the centreline Chine surface control points until the
roughly the required chine shape is obtained (something similar to the
that shown below).

11.    The final surface we want to create is the Hull Bottom surface.
Again to bond with the chine surface we need a surface with
compatible control point columns and stiffness. In a similar way as
outlined above, duplicate the Topsides surface and offset it vertically
by –3.5m (so that only the Topsides surface will be duplicated
uncheck the Respect Bonding check box). In the Surfaces window
rename the duplicate surface Hull Bottom. In the perspective view
we will end up with something similar to the following:

12.     Bond the top edge of Hull Bottom surface with the inside edge
of the Chine surface. To do this follow the same process as when the
Topsides surface was bonded to the Chine surface. In the Profile
view select the bottom row of the Hull Bottom surface with a select
box and edit the control point positions by selecting Controls |
Control Properties from the menu. Set the Offset position to 0m and
the height to –2.5m:

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13.     Now lets set the frame of reference and zero point. Go to the
Frame of Reference dialog box (Data | Frame of Reference), press the
Find Base button and set the DWL to –1.48 (or whatever the height of
your chine line is, this value may be found by placing the mouse at
the chine and reading the mouse coordinates at the bottom of the
Body Plan window). Press the Set to DWL button to find the Aft and
Fwd perpendiculars. Press OK to close the dialog box.
To set the zero point choose the Data | Zero Point menu option.
Select the Aft Perpendicular and Datum Waterline radio buttons.
Also make sure the Locked Zero Point check box is unchecked so that
the zero point will change with the aft perpendicular if it is moved.

14.     Check the surface outside arrows are pointing in the correct
direction in the Body Plan window (Display | Outside Arrows, if the
arrow is pointing inside click on the circle at the end of the arrow, this
should reverse the direction).

15.      Next step is to shape the forefoot in the Profile window. First
we must set the flexibility of the Topsides and Hull Bottom surfaces
to 3, to do this there must be at least 3 rows of control points in each
surface. In the Body Plan view add a middle row to each of the
surfaces using the Controls | Add Row menu option and place them in
a similar position as shown below:

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Now set the transverse flexibility values to 3 of the Topsides
and Hull Bottom surfaces in the Surfaces window.

the Control points to positions that give the required shape. Also you
may wish to raise the transom a little. When shaping in the Profile
and Plan views it is usually helpful to compress the view     :

17.     Switch to the Plan view and shape the plan as required.
Remembering that there are several layers of control points on top of
one another and if you wish to move them all they should be selected
with a box using the mouse (and the control point net needs to be
turned on, Display | Net | Show Net). Again shaping is aided by the
use of the compression tool:

18.     Now switch to the Body plan view and move control points
until the required hull shape is achieved. Here it is useful to have
section shapes to guide you in your fairing. Select Data | Grid

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Spacing from the menu and click the Add button and type 9 stations.
Then click on the Space button and select "Evenly along the length of
the model". When you click OK, the station positions will have been
automatically calculated. To add a section at the transom click the
Add button and enter 1 in the edit box. The default longitudinal
position is zero, click the Sort button and rename the station to st 10.
Click OK to close the window. Click on the show section button
to display the sections in the Body Plan window. It may also be
useful to turn the control point net off (Display | Net | Hide Net) so
that only the selected control point column is visible. Try and achieve
a similar shape to the following:

19.      Remember that the fairing process is iterative and to switch
between Body Plan, Profile, Plan and Perspective windows during the
final fairing process. Also make use of the fairing tools including the
porcupines       for showing curvature, the compression tool        and
different types of rendering in the perspective view (Display |
Render). Rendering showing Gaussian curvature is useful with blue
surface and red showing concave curvature. It is also much easier to
obtain a fair surface when the control point grid is kept as regular as
possible (i.e. control point rows and columns in straight lines), and as
a general rule with as few rows and columns needed to generate the
required shape.

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