Ø  Read the Data Import section in the Maxsurf manual.

Each of the different data import options is useful in different ways. Below there is a short tutorial where you will learn how to import a background image and scale it so that it can be used to re-model the design in the image.

Typical lines plan image of large cargo vessel.
(Linesplan.gif in the Training Samples folder)

Maxsurf allows you to import one background image in each view window. This means that the image above needs to be split up into 3 separate images; one each for Body Plan, Profile and Plan view.

Ø  In Maxsurf, open the Containership.msd sample model.

Ø  Display only edges and lock the surface for now. Hide the grid.

This design looks like the design in the image and we will use it as a starting point. It is always a good idea to open a design first before importing images. This helps when try to make the zero points of the model correspond to that of the surface model. Notice that the zero point of the containership is at the Aft Perpendicular and the Baseline. This is a convenient location because we can easily find this location in the image as well, which again helps to match them up.

Ø  Switch to Profile view window

Ø  Now go File | Import | Image Background and select the Linesplan_Profile.gif file.

You will now see something like this:

The zero point of the image and the scale still needs to be adjusted.

You can now set the zero point of the image:

Ø  From the Display menu, select Set Image Zero Point

Ø  Zoom in on the Aft Perpendicular of the image:

Ø  Set the zero point with the tip of the mouse cursor by clicking on the intersection between the Baseline and the Aft Perpendicular.

Ø  Zoom out by pressing the Home view button.

The zero point of the image has been matched with the zero point of the model

Next step is to scale the image to the Maxsurf coordinate system. I.e. when the ship is 190 m long in real world, we can scale the image so that it is 190 m in Maxsurf space. In Maxsurf you can do this by specifying a reference point. This point can be for example the Fwd extremity, the top of a superstructure or any other point of which the horizontal or vertical distance to the zero point is known. Currently the image is approximately 110 m long (you can measure with mouse cursor in Profile view if you like).

In this case, we know from the Lines plan that the LBP (length between the Perpendiculars) is 187 m. We can scale the image by telling Maxsurf where the Fwd Perpendicular is.

Ø  Zoom in on the position of the Forward Perpendicular

Ø  Display | Background | Set Image Reference Point

Ø  Set the Reference point with the tip of the mouse cursor by clicking on the intersection of the bow and the Datum Waterline:

This brings up the Background Image Reference Point dialog:

Ø  Specify 187 m in longitudinal direction and click OK

This will enlarge the background image:

Ø  Save the design as ContainerShip_Image.msd

Now we can do this in Plan view as well:

Ø  Repeat the steps above but now in Plan view window with the image file Linesplan_Plan.gif. The zero point is of course on the Centreline and at Aft Perpendicular.

Once you have completed that, you can also import the Linesplan_BodyPlan.gif.

Ø  Repeat the steps above, but now in Body Plan view. You will need to specify a Reference point which is any point on the Maximum Beam which is 14.8 m from the zero point in the transverse direction.

Ø  Save the design

The next step is basically starting a surface fitting process by resizing the start-model (ContainerShip.msd file in this case) to match the background image size. Maxsurf cannot resize a surface based on the Length of Perpendiculars, so you will have to measure the length overall of the background image.

Ø  Measure the length overall of the background image. This can best be done in Plan view and should be approximately 208 m.

Ø  Also measure the depth of the hull in Body Plan. This should be approximately 16.5 m

Ø  Unlock the Hull surface and resize it to a length = 208, depth = 16.5 m and beam = 29.6 m

Ø  Check your work in the different view windows.

Ø  Save your design.

Now, theoretically, in all view windows you should see the surface model roughly match up with the background image in overall size (not shape yet). In any case, what should not happen is that your surface model is smaller than the background image in for example Profile view but bigger in Plan view. This means that you have set the zero and reference points of the background image inaccurately in either (or both) of the view windows.

In this tutorial, the Lines plan image file is of very low resolution and inaccuracies are easily created in each of the view windows. In the example ContainerShip_Image.msd file you can see that the Profile view background image is far too small compared to the background image in Plan view (which seems to match the Surface model reasonably well - as does Body Plan view).

The next step in the surface fitting process would be to set up a grid that matches the buttocks, waterlines and sections of the lines plan image. After that, you can start shaping your surface to match the lines of the image; remembering the following order:

§   Corner control points

§   Edge control points

§   Internal control points

The surface fitting steps described briefly above are not covered in any further detail in this LearningMaxsurf training manual.

The other Data Import options should all be reasonable self evident with the information provided in the user manual.

One note that is worth including here is that DXF backgrounds work in much the same way as Image backgrounds except for:

§   No need to specify scales or zero point (these are inherited from the CAD drawing)

§   You can only import one DXF background in Maxsurf (instead of one for each view window). It is therefore recommended to convert your 2D DXF into a 3D DXF in your CAD application prior to importing.

Continue with the section on Data Export.