Important information

Consider the following important information before importing a NAPA Steel model to CADMATIC Hull.

• NAPA API version
• Items not imported
• Limitations and restrictions
  • Hull surfaces to shell plates
  • Main objects to plates
  • Limitation on the number of points in plate contour
  • Stiffeners to face plates
  • Stiffeners to bent profiles
  • Stiffeners to shell frames
  • Holes
  • Brackets
  • Cutouts
  • Seams
• Main objects with corrugation
• Mapping of Hull shapes to NAPA surfaces
• Material mapping

NAPA API version

The Import NAPA Steel function in CADMATIC Hull uses NapaObjectModel API version 2021.2. To ensure correct import results, the structural entities in the NAPA model to be imported to CADMATIC Hull should be compatible with NAPA version 2021.2 or later. All structural elements defined in earlier NAPA versions than 2021.2 may not import correctly to CADMATIC Hull.

Items not imported

The following items are not imported in the current version of the Import NAPA Steel function:

• Reductions that are not part of the main object (plate) contour
• Face plates on curved plane plates
• Holes in face plates and bent profiles. It is possible to create such holes in NAPA, but they are not supported in Hull and are not imported.

• Cutouts in pillars and bent profiles. These are not supported in Hull and are not imported.

• Some brackets. See Brackets below.

Limitations and restrictions

The following limitations and restrictions apply currently.

Hull surfaces to shell plates

Seams in the NAPA surface will split the main shell plate, resulting in multiple shell plates in the imported Hull model. The seams are converted into fixed value relations. See Shell Conversion.

Main objects to plates

In NAPA, the equivalent of plate is main object.

• Main objects that are exactly on the limits of the model will not be imported.
• If the main object is split with seams into multiple plates that have different thicknesses, it will be imported to Hull as one plate, and the plate's thickness will be the NAPA main object's highest thickness. The material of the plate will be that of the thickest part of the NAPA main object.
• In Hull, plates can only relate to other plates in cross section, hull, fixed values, and auxiliary lines.

• Topology defined as parametric curves is not supported, and will be imported as auxiliary lines.

Limitation on the number of points in plate contour

CADMATIC Hull has a limitation on how many points a plate contour can have. The maximum is 800.

Important: When importing main objects (plates), make sure that they do not have more than 800 points in their contour. Recalculation of plates having more than the maximum number of points on their contour will not be possible in Hull.

Important: We strongly advise to do the import in blocks, and not import the whole model all at once.

If you do not want to do the import in blocks, consider defining custom limits for the area to be imported.

Plates with a great number of points can also be split to ensure that the maximum number of points is not exceeded.

Stiffeners to face plates

In NAPA, face plates are created as boundary stiffeners that go along a free plate boundary.

A NAPA boundary stiffener that goes along the boundary of an opening is created as a bent face plate in a hole in Hull, as a sub-attribute of the hole (standard profile type attribute 452).

• Make sure that the boundary stiffeners are placed in such a way in the NAPA model that the resulting face plates in Hull can be created using at least three relations. An exception to this is a boundary stiffener that goes end to end along a single side of the plate. In such a case the resulting face plate will have just one relation, to its main plate.

• Items that are related to face plates (plates, profiles, face plates etc.) are not considered in the import.

Stiffeners to bent profiles

A NAPA stiffener that is not a face plate and has more than 2 points in its trace line is imported to Hull as a bent profile.

A bent profile has topological starting and end relations, and it is possible that an imported bent profile is related to other parts.

• In Hull it is not possible to construct a bent profile that is related to a profile in view. Therefore when importing a NAPA stiffener that has such a topological relation, the relation is replaced with a fixed value relation which is as close as possible to the natural touching point between the bent profile and the profile in view.

Stiffeners to shell frames

A stiffener whose main object is part of the shell is considered to be a shell frame. If such a stiffener is not defined in one plane in NAPA, i.e. its plane is not planar but curved, and therefore the stiffener is curved, it is not included in the import.

Holes

The following limitations and restrictions apply to holes currently:

• To be included in the import, the center point of a NAPA hole (opening) must fall within the limits set for the part of the NAPA model to be imported. If the center point of the NAPA hole does not fall within the limits, it will not be included in the import.
• NAPA reductions that are defined in the main object's (plate's) topology are imported to Hull as arbitrary holes.

Brackets

The following limitations and restrictions apply to brackets currently:

• NAPA brackets do not have relations to plates in view, only relations to plates in cross-section.
• Brackets related between three main objects in NAPA cannot be imported, unless there is a user-defined bracket in Hull that supports such relations. This is because there is no standard bracket in Hull that can be related to three plates in cross-section.
• Flanges on brackets are not supported, and will not be imported.
• Profiles on brackets are not supported, and will not be imported.

Cutouts

The following limitations and restrictions apply to cutouts currently:

• Cutouts around face plates are not imported.
• Cutouts cannot be converted to corner holes.

Seams

If seams are connected to other seams, they won't be imported correctly because the NAPA API doesn't provide this information. While the start/end points are available, they cannot be added as auxiliary lines, because the end points must be either on the plate contour, another seam, or around a hole. Therefore, these seams are only created up till the edge of the plate.

Main objects with corrugation

NAPA main objects (plates) with corrugated curves are imported either as plates with corrugation or as plates with corrugated profiles, depending on the depth of the corrugation. The depth value can be set in System Management > Import/Export > NAPA Steel > Connection Settings > Corrugation Limit.

Mapping of Hull shapes to NAPA surfaces

To maintain the topology of the NAPA model, that is, to ensure that the imported structural entities get relations in Hull, NAPA surfaces must be connected to CADMATIC Hull hull groups. This is done in NAPA, in the TAB*NUPAS_SHAPES table, where Hull group numbers are mapped to NAPA surface names. The NAPA project version that is imported to Hull must have this table.

Important: When defining the surfaces in the NUPAS_SHAPE table in NAPA, you must define all surfaces to be interpreted as starboard only hull groups, except those surfaces that should be interpreted as asymmetrical hull groups. This is because, apart from asymmetrical surfaces, CADMATIC Hull only uses the starboard side hull surfaces and mirrors them to the port side. This means that a surface that should be available in the port side in CADMATIC Hull should be defined as a starboard surface in NAPA.

Surfaces that cannot be mapped in the NUPAS_SHAPES table must be mapped in Shell Conversion in System Management > Import/Export > NAPA Steel > Connection Settings.

Note: During the import the system checks the surfaces that are mapped to hull groups in the NUPAS_SHAPES table and in the Shell Conversion settings in System Management. Those surfaces that start as non-planar but are actually planar within the import limits are treated as planar. This way construction gets related to planar plates as much as possible, instead of getting related to hull groups, which improves the topology of the import. This check is not performed if the Only shell plates import option is selected. Also, surfaces mapped as hull group 0 are always imported as non-planar (hull lines or shell plates).

Syntax

Shape (Hull group number) followed by Name (NAPA surface name). Numbers 0-2999 are for normal shapes, and numbers >3000 are for hull reference surfaces. For example:

0 HULL

1 DECK

2 TTOP

Note: If the import database is not used as the active database, Hull Shape Import must be used to get the surfaces from the NAPA database before the import.

Material mapping

The import functionality compares the materials in the material tables of NAPA and CADMATIC Hull. Make sure that a mapping of materials exists before importing, by creating a table of materials in Hull. The table should contain the same materials as the NAPA material table (Hull material codes that match the NAPA material names), including the density property of the materials.

• If a material in the NAPA material table is not found in the Hull material table, the system shows a warning before starting the import, and the missing material(s) can be added to the Hull material table. If the import is started regardless of missing materials in the Hull material table, objects are imported with the name used in the NAPA material table.

• The densities of the materials must match. The system shows a warning if the same material with a different density is found in both tables.