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Hull and Outfitting

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Create Category for Joints

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  • Last UpdatedNov 21, 2025
  • 5 minute read

Structural joints are catalogue components that are referenced via the Spref attribute of an SJOI element and are associated with the owning and attached members of the connection.

Joints may be complex or a simple, depending on the engineering requirement, that means, the time and effort spent on their creation.

Joints can consist of positive and/or negative 3D geometry components and may be any shape that can be defined by these components.

A joint require a 3D Positive Geometry Sets and/or a 3D Negative Geometry Set, a Pline Set, a 3D Point Set, a Data Set and a Specification to function correctly.

Joints are usually defined parametrically such that a single definition may be used for different size combinations of the Owning and Attached section’s Gtype.

A Joint Category must reside below a STSE which in turn must reside below a CATA element.

Create Category for Joints

  1. Select Create, then select Catalogue to open the Create Catalogue Form. Create a new Steelwork Catalogue in the database hierarchy with the purpose set to STL.

  2. Select Create, then select Section to open the Create Section Form. Create a new Steelwork Section in the database hierarchy with the purpose set to STL.

  3. Select Create, then select Category for Joints. The Category for Joints form is similar in layout to a standard Create Category Form, but contains added sub forms specific to Steelwork Joints.

    Before entering data, it is good practice to sketch the joint to help determine what geometry components are required, where the origin will be, what the axes will be, what the parameters and design parameters (if any) will be and any other data that may be applicable.

    To achieve the above layout, two Negative Structural Extrusions (NSEX) will be used. The Posline of the SJOI will be NAR, the SLOO for the NSEX lies in the XZ plane. with respect to the Pline axes, the Paaxis and Pbaxis of the SEXT will be set to Z and -X respectively.

    The NSEX will require five vertices whose positioning attributes will be expressed in terms of owning, attached and design parameters.

    The negative extrusion will be created at the joint origin and then moved to its correct location.

    This joint has one design parameter, that means, Rathole Radius, and the geometry uses some parameters from the owning and attached sections. Therefore, for Model Parameters, Design Parameters and Owning Parameters and Attached Parameters must be set.

  4. Select Settings, then select Model Parameters from the main menu to display the Model Settings Form.

  5. Set Design Parameter No. 1 to 25.

  6. Set the Attached Parameters 1 to 200 and 2 to 120

  7. Set the Owning Parameters as follows:

    1 - 600

    2 - 200

    3 - 100

    4 - 10

Create the Joint Geometry

  1. Click on Negative Geom in the Model References part of the form.

    The Negative Geometry References sub form opens.

  2. Select NSEX from the drop-down menu.

    The Negative Extrusion Definition sub form opens:

  3. In the A Axis (PAAX) enter Z.

  4. In the B Axis (PBAX) enter X.

  5. In the Height enter (APAR[2] + 20mm).

  6. Check Tube Flag and leave the remaining fields as the default value.

  7. Click Modify Points.

  8. In the Modify Points form populate the following data:

    Vertex

    PX

    PY

    PRAD

    1

    0

    0

    0

    2

    ( OPAR[2 ] / 2 - OPAR[3 ] / 2 )

    0

    0

    3

    ( OPAR[2 ] / 2 - OPAR[3 ] / 2 )

    (OPAR[4])

    0

    4

    ( OPAR[2 ] / 2 - OPAR[3 ] / 2 + DESP[1])

    (OPAR[4]

    0

    5

    ( OPAR[2 ] / 2 - OPAR[3 ] / 2 + DESP[1])

    (OPAR[4] + DESP[1])

    (DESP[1])

    6

    0

    (OPAR[4] + DESP[1])

    0

  9. Click OK to close the Modify Points form and return to the NSEX.

  10. The NSEX must be moved to its creation position, enter the following values in the position attributes:

    • PX 0

    • PY (-OPAR[1] / 2)

    • PZ (-OPAR[2] / 2 - 10mm)

    The second negative extrusion is an exact copy of the first except the Pbaxis is in the opposite direction.

  11. Click Copy to create a copy of the original NSEX element and change the PBAX field to –X.

    Create the Pline Set

    The Pline Set will contain a single Pline, the NA. This will be used for all joints unless a joint requires more than one Pline, in which case a new Pline Set will be required which will still include an NA Pline.

    1. Click on Pline Ref in the Model References part of the form to open the Pline Definitions sub form.

    2. Create a new Pline with a Pkey set to NA and set the description to Neutral Axis.

    3. Leave all other attributes with the default value.

      Create Point sets

      For this joint there will be a Ppoint at each vertex of the NSEX and one on the circumference of the rathole. The Ppoints will be located on the centerline of the attached member.

      1. Click Point Ref in the Model References part of the form to open the Point Set References sub form.

      2. In the pulldown select Cartesian P-Point PTCA to expand the appropriate input form.

      3. New create 14 P-Points and populate the values as in the table below:

        NO.

        PX

        PZ

        1

        (OPAR[1] / 2 – OPAR[4] – DESP[1])

        0

        2

        (OPAR[1] / 2 – OPAR[4] – DESP[1])

        (OPAR [2] / 2 – OPAR [3] / 2)

        3

        (OPAR[1] / 2 – OPAR[4] – DESP[1] / SQRT(2))

        (OPAR[2] / 2 - OPAR[3] / 2 + (DESP[1] / SQRT(2)))

        4

        (OPAR[1] / 2 - OPAR[4])

        (OPAR[2] / 2 - OPAR[3] / 2 + DESP[1])

        5

        (OPAR[1] / 2 - OPAR[4])

        (OPAR [2] / 2 – OPAR [3] / 2)

        6

        (OPAR[1] / 2)

        (OPAR [2] / 2 – OPAR [3] / 2)

        7

        (OPAR[1] / 2)

        0

        8

        (-OPAR[1] / 2 + OPAR[4] + DESP[1])

        0

        9

        (-OPAR[1] / 2 + OPAR[4] + DESP[1])

        (OPAR [2] / 2 – OPAR [3] / 2)

        10

        (-OPAR[1] / 2 + OPAR[4] + DESP[1] / SQRT(2))

        (OPAR[2] / 2 - OPAR[3] / 2 + (DESP[1] / SQRT(2)))

        11

        (-OPAR[1] / 2 + OPAR[4])

        (OPAR[2] / 2 - OPAR[3] / 2 + DESP[1])

        12

        (-OPAR[1] / 2 + OPAR[4])

        (OPAR [2] / 2 – OPAR [3] / 2)

        13

        (-OPAR[1] / 2)

        (OPAR [2] / 2 – OPAR [3] / 2)

        14

        (-OPAR[1] / 2)

        0

      Create Data Set

      The Data Set only requires one DATA element for the design parameter.

      1. Click Data Ref in the Model References part of the form to open the Data References sub form.

      2. In the Description field, enter Rathole Rad.

      3. In the Key, enter RRAD.

      4. In Definition, enter Design Parameter.

      5. Enter 1 in the No field.

      6. From Type, select Distance.

      7. Set the Default to (25).

      8. Click Apply.

        Now that a Category has been created, a part world and specification can be created which can be used within Design.

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