After you have setup your surface to be roughly the right size and inserted the number of rows and columns that you expect you will need to achieve the required shape, there are a few things you have to do before you can start manipulating the shape of the surface.

Note that the order in which things are done in this tutorial is not a set sequence of steps and you are free to do whatever you like at any point during the design process. The sequence in this tutorial ensures that you have for example your surfaces roughly the right size before you setup your grid so that you only have to do that once.

 Watch a short video that shows you how to setup the Frame of Reference and the Zero Point and define the Grid. [Web | Disk]

Set Surface Properties

Before moving the control points in your design, you should review the surface properties. In general, you should select a B-Spline surface with the maximum stiffness that will give you the surface you require. This will be an iterative process, since the number of control points defining the surface limits the maximum stiffness.

Ø  Rename the surface and set the surface stiffness to the values in the dialog below

Ø  Make sure that the surface is symmetrical.

Ø  Save your design as MyFirstDesign_Preparation.msd

We will look at the other surface properties later, for the moment this is all you need.

Set Frame of Reference and Zero Point

Before proceeding to far into the design, you will want to set up a Frame of Reference and Zero Point from which measurements are taken.

Ø  First read the Maxsurf Coordinate System section in the Maxsurf manual

Setting the Frame of Reference and Zero Point is a circular process since the Zero Point is dependent on the Frame of Reference and the baseline is measured relative to the Zero point. Every user has his/her own way of dealing with it, but by following the next procedure you can avoid getting confused:

Ø  First, select Data | Frame of Reference

This will bring up the Frame of Reference dialog which allows you to position the datum waterline, baseline and fore and aft perpendiculars:

Ø  Press the <Find Base> button

Ø  Set DWL relative to the baseline

For example if the DWL is 3 m above the baseline and the baseline is at –8, then the DWL value is –5 m (and not 3 m).

Ø  Set the perpendiculars either by pressing the <Set to DWL> button, or typing the values below numerically

Ø  <ok>

Now that you have the baseline, DWL and perpendiculars set, you can set the zero point based on those positions. Every user will have his/her own preference for the location of the zero point, but in this tutorial we will use the Aft Extremity for the horizontal, and the Baseline for the Vertical position.

Ø  Go to Data | Zero Point

Ø  Set the dialog as below

If the longitudinal position of the zero point is set to the fore or aft extremity, the “Locked Zero Point” tick box controls whether the zero point moves as the design is changed. For example: If the zero point is not locked and the design is lengthened, the zero point will move. This is usually not what you want. If the zero point is locked, it will not move with the extremities. This makes making coordinate measurements for reference points a lot easier.

Insert a Grid

Before you can start modelling, you need some way to visualise the surface shape while you are modelling. At this stage of design it is therefore necessary to create a grid of sections, waterlines, buttocks and maybe also diagonals. These contours may then be displayed on the design while modelling.

Ø  Go to Data | Grid Spacing

You’ll see the following dialog appear:

The dialog can be divided up into the following regions:

1.      Select the type of grid you want to work on, i.e. Sections, Buttocks, Waterlines or Diagonals

2.      Commands to Add, Delete, Sort or Space the grid type selected in 1.

3.      Displays the current grid locations for the grid type selected in 1.

4.      OK and Cancel to confirm or undo all changes made in the dialog.

Ø  Select Sections

Ø  Click on the Add button to add Sections:

Ø  Add 20 Sections and click OK

This will return you to the Grid Space dialog, which now shows the Grid on the left (region 3 in the image of the Grid Space above). Next step is to specify the location of the Section lines. You can do that for each section individually by typing in region 3 directly, or – much faster:

Ø  Click the Space button:

The Space dialog allows you to Space any number of selected sections over any distance you specify. In the Maxsurf Intermediate training we will look at some more advanced use of this dialog, but for now:

Ø  Space the Sections Evenly along the Length of the model and click OK

Notice how all Sections are evenly spaced from 0 to 40 m:

Do NOT click OK in this dialog yet. You will first:

Ø  Insert 4 Buttocks spaced evenly along the width

Ø  Insert 5 Waterlines spaced evenly along the depth

Ø  Click OK now

Ø  Go to Perspective window, switch the Net off, Half on, and display Sections, Buttocks and Waterlines:

You can now also Toggle the Grid display on/off from the Display | Grid menu or using the  toolbar button. Note that this adds a lot of additional lines to the display, especially in Perspective view, and may confuse you. Remember that efficient modelling is all about displaying the least amount of information necessary.

Ø  Remember to save your model

Ø  Save your design as MyFirstDesign_Preparation.msd

You now have a basic surface with a Zero Point, Frame of Reference and a grid. The surface is approximately the correct length.

Continue with the section on Modelling .