Base points

Last updated March 12, 2019 by Tekla User Assistance

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Base points

Base points

The base points (control points) allow you to use a coordinate system based on the civil origin or other coordinate system for interoperability and collaboration. For example, you can use base points when inserting reference models, exporting IFCfile format commonly used in BIM that facilitates software interoperability

IFC is an open specification developed by the IAI (International Alliance for Interoperability).

Model can be exported into an IFC file.

models, in drawings, in Layout manager , and in reports and templates.

Civil origin is the datum point or fundamental benchmark point of the national land survey network.

When you use base points, you can keep the coordinates small and locate the model wherever needed. You can create as many base points as you need, and select one of those to be the project base pointbase point that sets the point of origin for a project if the model has several base points

A project can have only one project base point.


Note the following:

  • Reference modelmodel which the designer can use as an aid when building another model

    A reference model is created in Tekla Structures or in other software and can be inserted to Tekla Structures. The reference model appears together with the model but it is not modified by Tekla Structures. The user can snap to reference model points.

    For example, an architectural model, a plant design model, or a heating, ventilating, and air-conditioning (HVAC) model can be a reference model.

    should not have any additional lines to the origin.
  • Reference models should not include objects that are very far from each other because otherwise using the model may get difficult.
  • Tekla Structures native objects including reference models should not be inserted very far from the Tekla Structures model originglobal coordinate system point of origin used for the model

    Model origin is the default project base point.


Define a base point

You can define base points in Project properties. In case you need to import or export a reference model, you need to know the coordinates of the reference model that you are importing, or the coordinates that you want to use in IFC export.

  1. Open a Tekla Structures.
  2. Click File > Project properties > Base points to open the Base point dialog box.
  3. Fill in the needed information:

    Name , Description Enter a name and a description for the base point.
    Coordinate System Enter the name of the coordinate system you are using.
    East coordinate (E) Enter the East coordinate (E) that represents the X coordinate related to the civil origin.
    North coordinate (N) Enter the North coordinate (N) that represents the Y coordinate related to the civil origin.
    Elevation Enter the Elevation that represents the Z coordinate related to the civil origin.
    Latitude , Longitude

    Enter the Latitude and Longitude of the base point to be used in the IFC export.

    Latitude and Longitude is additional information, which some software can use. In the IFC file, this is written to IFCSITE information.

    If the total number of digits in Longitude is more than 15, the value is rounded up to the nearest if it is > 99.999999999999999999.

    To convert Latitude and Longitude information between decimal format and degree/minute/second (DMS) format, see Convert Latitude/Longitude to decimal.

    Location in the model Pick or enter a location for the base point in the Tekla Structures model. The distance is measured from the model origin. The location needs to be near the model origin, preferably less than 1000 m from the origin.
    Angle to North Pick or enter the Angle to North , which is the angle between Y and North directions. The maximum number of decimals for the angle is 13.
    Project base point If you want to set a coordinate system as the project base point, select a base point from the list at the top and then select the Project base point check box.
  4. Click Modify to save the base pointpoint in a model that is used to define a starting point in surveying and that is used as an anchor point in coordinate and height transformations

    A Tekla Structures project can have several base points but only one of them can be the project base point.

    Base points allow the use of another coordinate system needed for interoperability and collaboration. Base points can also be used in drawings, and in reports and templates. Model origin is the default base point in Tekla Structures.

    Base points are also called control points.


    A blue symbol is added in the model.

    If you later on make changes to the base point, the base point location in the model changes according to the location or rotation changes you make in the Base point dialog box when you press Enter or click another input field, and there is no need to click Modify.

    Now you can insert a reference model, or export an IFC model using the defined base point.

Set a coordinate system as the project base point

One base point can be set to be as the project base point. Model origin is the default project base point value if the model does not contain any base points, or if none of the existing base points has been set to be the project base point. You can check and change the current project base point through File > Project properties > Location by.

Note that it is not recommended to change the project base point temporarily during a project.

  1. Click File > Project properties.

    You can see the current project base point in the Location by box.

  2. To change the project base point, click Edit , and select a new project base point from the Location by list.
  3. Click Apply.
Tip: You can also set a base point as the project base point in the Base point dialog box by selecting a base point from the list at the top and then selecting the Project base point check box.

Insert a reference model using a base point

Before you can insert a reference at the base points, you need to create a base point in your model. To create the base point, you need to know the coordinates of the reference model that you are importing.

  1. Open the Reference Models list by clicking the Reference Models button in the side pane.
  2. In the Reference Models list, click the Add model button.
  3. In the Add model dialog box, if you have any previously created reference model properties files, load the desired file by selecting the file from the properties file list at the top.
  4. Browse for the reference model by clicking Browse....
  5. In Group , select a group for the reference model, or enter a name for a new group.

    If you do not enter a name for the group, the reference model is inserted in the Default group.

  6. In Location by , select the base point you want to use.
  7. Click the Add model button. Tekla Structures inserts the reference model relative to the selected base point by using the coordinate system values, elevation and angle in the base point definition in the model Project properties.

Export an IFC model using a base point

Before you can export an IFC file using a base point, you need to create a base point in your model.

  1. Click File > Export > IFC to open the Export to IFC dialog box.
  2. In Location by , select a base point that you have created.
  3. Fill in other necessary IFC export information.
  4. Click Export. The base point option exports the IFC model relative to the base point using the coordinate system values, elevation, latitude, longitude and angle in the base point definition in the model Project properties.

Base points in drawings

It is possible to use base-point-defined coordinate system values in drawings. If you change the project base point Z or the elevation value, the level value will change accordingly when a drawing is opened.

  • Base point data can be used in drawing and view level to set the coordinate system. The base point can be used instead of datum offset.
  • When the base point is set, level attributes and template attributes in marks provide values in the specific base-point-defined coordinate system.
  • This setting affects level marks and attributes that end with _BASEPOINT.
  • When the base point is set at the drawing level, the _BASEPOINT template attributes can be used in drawing templates.

You can set Location by in drawing viewview that includes selected model objects or an area in the model, that is represented in a drawing

A drawing view is a container for model and drawing objects.

A drawing can include several drawing views, which usually are two-dimensional views, plane views, to the model.

Examples of drawing views in Tekla Structures include main views, section views, single-part views, and 3D views.

properties to use model origin, project base point or any base point defined coordinate system. Location by uses the project base point as the default value.

The datum level only affects the attributes TOP_LEVEL and TOP_LEVEL_UNFORMATTED when Location by is set to Model origin or to the project base point that is in the model origin.

To change the Location by value:

  1. In an open drawing, double-click the drawing view framesolid frame around all the contents of a drawing view

    Drawing view frame can be used when modifying properties of a single drawing view. Drawing views can be dragged using the drawing view frame.

    to open the View Properties dialog box.
  2. On the Attributes 2 tab, set Location by to a new base point, or to the model origin.
  3. Click Modify.

Example of base point usage in a drawing

In the following example, do the following:

  1. Create a slabplate that represents a concrete structure

    In Tekla Structures, a slab is created by picking three or more points.

    Slab may be part of a floor, for example.

    with a thickness of 200 mm with the slab's top at the level 0 in the model.

  2. Create a new base point "Control point 1" with elevation 20000 mm.

  3. Create a GA drawingdrawing that is created from one or more model views and that shows information needed to understand the general arrangement of structural elements on a project

    General arrangement drawings show how parts, assemblies, cast units, or pour objects are located in a building.

    in plan view.

  4. Open the GA drawing, double-click the view frame to open the View properties dialog box.

  5. On the Attributes 2 tab, you set Location by to the new base point (Project base point) "Base point 2" and click Modify.

  6. Add a level markassociative annotation object that represents the elevation of a point

    using the following template attributes:

    • COG_Z
  7. Reopen the drawing.

    Note that changing the value does not update the template attributeattribute in a template object that Tekla Structures uses to calculate and display information from a model database

    Template attributes represent object properties.

    automatically but after reopening the drawing.

Base points in Layout manager

You can use base points in Layout manager when defining the location of layout points.

  • You can use base points as location coordinates when exporting and importing layout points.
  • When you add, modify or delete base points, you need to reopen or refresh Layout manager to make the changed base point data available in Layout manager.

Base point in reports and templates

You can inquire project base point and current base point value in reports and templates.

The following table lists the template attributes where you can use _PROJECT and _BASEPOINT at the end, for example, ASSEMBLY_BOTTOM_LEVEL_PROJECT or ASSEMBLY_BOTTOM_LEVEL_BASEPOINT. Note that _BASEPOINT uses the current base point in the same way as the workplane uses the current workplane. If there is no current base point defined, _BASEPOINT provides values relative to model origin (Global).

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