Hull lines

Generally speaking hull lines can be seams, butts, dimension lines, hull boundary lines or groups intersection lines.

Seams and butts represent the shell plate boundaries.
Dimension lines indicate transition areas in the hull shape. They can also be used as supporting lines for creating shell plates and shell frames.
Hull boundary lines are dimension lines on the outer edges of hull groups at the boundaries of adjacent hull groups.
Groups intersection lines are hull lines at the intersections of the shapes of hull groups. Two intersecting hull group shapes get identical groups intersection hull lines along their intersecting shapes.

In addition there are some extra hull line types. These hull line types include angled curves, knuckles, frame lines, buttocks/verticalsand water lines.

Hull lines can be shown in the shell view by selecting the desired hull line types in the Show Hull Lines function, and they can be hidden with the Hide Hull Lines function.

The hull line types are as follows:

Angled curves – These lines border flat areas to curved surfaces. They come with the external shape database and are always shown. Angled curves are designated by number in ascending order.
Knuckles – These lines border curved surfaces. They come with the external shape database and are always shown. Knuckles are designated by number in ascending order.
Dimension lines – These lines are primarily used as support lines in curved surfaces. They may have either come with the external shape database, or have been created in the Shell application and are stored in the user shape database. In both cases they are optional lines. When dimension lines are present in both the external and user shape databases, they will appear in the hull line list twice, and can be separately added to the drawing. Dimension lines are designated by number in ascending order.
Frames – These lines are drawn in length direction. They can indicate the frame positions, but can also be drawn at any desired length position. Their curvature is determined by the surfaces in the external shape database which they are projected onto. Frames are designated by frame number in ascending order.
Verticals – These lines can be drawn at any desired breadth position. Their curvature is determined by the surfaces in the external shape database which they are projected onto. Verticals are designated by their position in millimeters in ascending order.
Water lines – These lines can be drawn at any desired height position. Their curvature is determined by the surfaces in the external shape database which they are projected onto. Water lines are designated by their position in millimeters in ascending order.
Dimension lines (hull boundary lines) – These lines are a special type of dimension lines on the outer edges of hull groups. They also exist at the boundaries of adjacent hull groups, each hull group having its own boundary line at the hull group border. Hull boundary lines have numbers starting from 1.1. Decimal .1 indicates that the line is a boundary line. Subsequent lines are numbered using an increment of 1 (1.1, 2.1, 3.1, ...).
Groups intersections – These lines are located at the intersections of the shapes of hull groups. Two intersecting hull group shapes get identical groups intersection hull lines along their intersecting shapes.

Group intersection line numbers are expressed as <intersecting_groupnumber>.<line_number>, where the first part is the hull group with which the current group is intersecting, and the second part is the line number. The first part can be up to 4 digits, and the second part is 3 digits. In the case of intersecting hull groups 1 and 2, 2.001 is line number 1 in group 1, and 1.001 is line number 1 in group 2. Line number 100 in group 2 would be 1.1.
Butts – These lines primarily border shell plates in length direction. They may have either come with the external shape database, or have been created in the Shell application and are stored in the user shape database. These lines are always shown. Butts are designated by key number in ascending order.
Seams – These lines primarily border shell plates in breadth and/or height direction. They may have either come with the external shape database, or have been created in the Shell application and are stored in the user shape database. These lines are always shown. Seams are designated by key number in ascending order.

More information

The help topics below provide information on the following subjects:

How to add, modify and delete hull line ranges.
How to add and modify hull lines to your shape.
How to delete and recalculate hull lines.
How to insert multiple hull lines.
How to define extra hull line properties.