Maxsurf contains several commands that allow you to manipulate whole surfaces. These commands generally apply to the current surface, that is the last surface selected or modified. If you are unsure as to which surface is the current surface, you can check the list of surfaces in the additional menu that appears when you place the cursor on the Properties item in the Surfaces menu. Alternatively, you can ensure that the surface you wish to work on is the current surface by selecting any control point in the surface.

Maxsurf has a number of standard shapes, which may be added to a design. They are as follows:

Box

This is a box shaped prism; the primary axis may be selected to be orientated in the longitudinal, transverse or vertical direction, this will determine where the open ends are. The length, width and height are the dimensions in longitudinal, transverse and vertical directions respectively.

Additional surfaces to close the open ends of the prism may be added if desired.

The box is placed on the centre line of the design. If the Symmetrical box is ticked, either a full or half model may be selected. For shapes that lie symmetrically on the centreline, it is best to select the Half Model on Centreline option. To add a complete box, away from the centreline, tick the Symmetrical box and select the Full Model button, then move the box away from the centre line to its desired location using the Move command from the Surfaces menu. If the box appears symmetrically on both sides of the vessel, you can then turn on the symmetry flag for the box's surfaces.

Cylinder

This is a circular or elliptical cylinder, the options work in the same way as the box.

Sphere

This is a circular sphere of specified radius. The various symmetry options are the same as for the box.

Hemisphere

This is a circular hemisphere of specified radius, which may or may not be closed with a disk. The hemisphere may be orientated in the longitudinal, transverse or vertical direction.

The illustrations below show the different effects that may be achieved with the symmetry options. In addition, the front and back ends of the box could have been closed with two additional surfaces if the Close Ends option had been ticked. (Box#1 is the top part of the box and Box#2 is the bottom; Box#3 and Box#4 are the mirrored surfaces.)

Non-symmetrical model

Symmetrical half model on centreline

Symmetrical full model on centreline made up of four non-symmetrical surfaces

Symmetrical model offset from centreline after move command and changing symmetry flags

When adding a surface, it is possible to select from a range of different surfaces in the Add Surface menu.

To add or delete surfaces from the list, which appear in the Add Surface menu, use the Edit Surface List command from the Add Surface sub-menu under the Surface menu.

To delete surfaces from the Surfaces list, select the surfaces to be deleted then click the Delete button.

To add surfaces from your existing design to the surface list, click the Add button then choose the surfaces from your design that you wish to add to the list.

Choosing Delete Surface  presents a dialog that allows you to select surfaces for deletion. Simply click on those surfaces you wish to delete and click OK.

Multiple surfaces may be deleted at the same time, and a surface that is bonded to another may be deleted without the need to unbond first.

This command duplicates the selected surfaces.

·   Select Duplicate Surface from the Surfaces menu.

·   Select the surfaces to be duplicated.

·   Click OK

A number of duplicates may be made at one time and these can be offset from the original, and one another, by the specified longitudinal, transverse and vertical spacings. If the Respect Bonding box is ticked, surfaces which are bonded will be selected and copied together.

Surfaces may be selected and moved relative to one another. This can be achieved by freeform dragging of the surface or by typing in a numerical offset.

Freeform Movement:

Movement is made in the plane of the window that is being used, or in the case of the Perspective window, in the plane most perpendicular to the current view. To select a surface for movement

·   Select Move Surface - Freeform from the Surfaces Menu.

The move cursor will be displayed.

·   Position the cursor over any control point.

·   Click and drag the surface to the new location.

An outline of the surface will display the position of the surface while it is being moved.

·   Release the mouse button.

On releasing the mouse button the surface will be displayed again at the new location.

Move Surface will move all surfaces bonded to the surface that is being moved. Note that all these surfaces must be unlocked.

Numerical Movement:

To move surfaces by a specified amount:

·   Select Move Surface - Numerical from the Surfaces Menu.

·   Select the surfaces to be moved and specify the amount that they should be moved in the longitudinal, transverse and vertical directions.

Locked surfaces or those which are bonded to locked surfaces cannot be selected.

The Size function allows a designer to scale and re-proportion a surface or group of surfaces by their principle dimensions. This function is particularly useful when modelling geometrically similar variations from a parent design, and also allows precise specification of principle design parameters.

To resize a design

·   Select Size from the Surfaces menu.

·   Select which surfaces you wish to resize.

Do this by selecting the surface names from the check boxes on the left hand side of the dialog. When a single surface is selected the size displayed will be the overall dimensions of that surface. When multiple surfaces are selected the size displayed will be the overall dimensions of all selected surfaces.

·   Select whether you wish to use proportional scaling.

For example, if you wish to maintain a length/beam ratio, tick the boxes of the dimension to be scaled proportionally (length and beam). When any of the dimension boxes are changed all boxes selected for proportional scaling will be changed in proportion.

Similarly, length, depth and beam may be scaled simultaneously, to produce a geometrically similar vessel, by ticking all three boxes. The desired length, depth or beam may be entered and all dimensions will be scaled proportionally. The dimensions will follow in proportion from the time that their proportional scaling boxes were ticked.

·   Select and edit the appropriate size boxes to alter the size.

You may do this by either editing the text directly or by using the scale up / scale down arrows at the right hand side of the size boxes. Dimensions may be entered in any units by specifying the appropriate suffix.

Markers may be scaled in the same proportion as the hull or may be left as they are. Tick the re-scale markers box to scale the markers with the surfaces.

You can size different surfaces by different amounts. This can be done by:

·   Selecting the first surface(s) you wish to resize

·   Resize them (as described above)

·   Deselect these surfaces and select the other surfaces you wish to resize

·   Resize these surfaces

·   Repeat for all the surfaces you wish to resize

·   Click OK

Surfaces may be flipped about specified planes: longitudinally, transversely or vertically. The actual mirror plane may also be specified, and need not be about the origin. At the same time you may also create a duplicate of the original surfaces.

·   Select Flip Surfaces from the Surfaces menu.

·   Select the surfaces you wish to flip.

If you are duplicating the surfaces, they need not be unlocked since the original surfaces will remain unchanged. If you are not duplicating the surfaces then they must be unlocked. If you choose Respect Bonding, bonded surfaces will be selected together. If you are not making duplicates, all the bonded surfaces must be unlocked.

·   Specify the reflection plane.

For example, if you wished to make a symmetrical catamaran hull, with a centreline spacing of 8m, you would design one side of the hull, move it transversely 8m then flip and duplicate it about the 8m transverse plane.

Flipping about the longitudinal direction could be used to produce a double-ended design.

The rotation dialog allows multiple surfaces to be rotated simultaneously around a specified centre of rotation. Surfaces to be rotated are selected by clicking in the list of surface names.

The centre of rotation is specified numerically, and is displayed in the drawing windows as a small circle:

The selected surfaces will be rotated about the rotation point by the angles chosen.

The centre of rotation (Reference Point) may be moved by double clicking on it in one of the design views and entering its new position numerically:

Two surfaces can be aligned by selecting one control point from each surface. The second control point will be moved, along with its entire surface, so that it aligns exactly with the first control point.

To align two surfaces

·   Select a control point from the surface to remain fixed.

·   Hold down the Shift key.

·   Select a control point from the surface to be moved.

·   Select Align  Surfaces from the Surfaces menu.

The second surface you selected will be moved so that the two control points become coincident.