Other Information
Grid lines and construction lines
Please be aware that there is a clear difference between Grid objects and Construction Line objects within the Tekla Structural Designer software :-
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Construction Lines are view specific objects and only appear on the view that they were created in.
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Construction Lines will not be exported to Revit.
Grids transferred from Revit into Tekla Structural Designer
For gridlines, all gridlines in the model will be transferred. There are no practical limitations to the symbols used for the gridline references or the level references. We would obviously recommend the use of clear and concise references for your own benefit though.
For initial imports into Revit (i.e. No existing Revit model exists)
All grid information from Tekla Structural Designer will be imported into Autodesk Revit using identical element definition points.
As the amount of grids used in the Tekla Structural Designer model may not meet the requirements of the Revit user, extra grids may be removed or new entries added to suit their needs.
For merging results into Revit (i.e. Returning information into an existing Revit model)
When merging results from Tekla Structural Designer into Revit, the API restricts the modification of existing grid objects.
If grids have been moved, lengthened or shortened within Tekla Structural Designer, the API requires the deletion of the existing grid and its replacement with a new grid object.
As this will have an effect on any predefined dimensions or sheets within Revit, we recommend that grids are not included in any updates to the Revit model.
Construction levels
Floor Setting
When generating levels within Tekla Structural Designer, it is important to understand that not all levels need to be transferred using the Integrator.
For levels generated in Tekla Structural Designer, only levels that have been flagged as Floor items will be exported. The exception to this rule is the lowest most entry in the dialog, which is ALWAYS exported, regardless of the Floor flag setting.
E.g. When looking at the example below, we find that four levels would be exported. Three of the levels are flagged as Floor whilst the lowest most level is always exported.
Level Type
Level entities in Tekla Structural Designer can be defined as Structural Slab Level (SSL), Top of Foundations (TOF) or Top of Steel (TOS). Concerning the integration process with Revit, this affects the vertical slab location.
Where levels are defined as Top of Steel, the slab will be offset equal to its depth so that the underside of the slab is located in line with the level entity.
Where levels are defined as either Structural Slab Level or Top of Foundations, the slab will not be offset. The top of the slab will be in line with the level entity.
Level Source
Tekla Structural Designer can use the concept of source levels to duplicate the content and simplify the modeling process. It is important to note that Revit has no concept of duplicate floors within the software, therefore duplicate levels are imported into Revit as independent unique levels.
If this model is then returned from Revit to Tekla Structural Designer, the source/duplication settings are reset during the merge process and all levels are flagged as unique.
No items will be physically lost as part of this change and the flag can be reapplied if necessary.
Level transfer from Revit into Tekla Structural Designer
When exporting models from Revit, please note that only levels containing a structural node will be exported.
For levels created when importing a model into Tekla Structural Designer, levels will be generated where either:-
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A level has been exported from Revit (see following section)
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Three or more beam or joist members are on the same horizontal plane
Working with real world coordinates
It is usual to find Revit models located to real world coordinates by use of the Specify Coordinate at Points or the Project Base Point features.
It is usual to find analysis and design software requiring models to be generated around the 0,0,0 base datum to avoid rounding errors or any other sort of numerical discrepancies from occurring. Therefore, most Analysis and Design software packages do not support the use of real world coordinates within projects.
To remove this as being a potential issue from any integration processes, Tekla Structural Designer will allow users to relocate models from real world coordinate positions during the import process.
When using the BIM Import command, the Relocate Import Model dialog will show the coordinate range of the incoming model on the right hand side. Please note that the Project Base Point entry is not directly recorded to the CXL file format and so users should liaise with the Revit user to be able to correctly relocate the incoming model to suit.
Please note that a similar dialog is also shown during the Export to Revit command wizard. Users should ensure that the same distances that were used to import the model into Tekla Structural Designer are also used when exporting data from Tekla Structural Designer.
Failure to use the same distances may result in the import of updates into Revit relocating the model to a different location.
End releases
End release conditions are transferred between Revit and Tekla Structural Designer.
Therefore, for models originating from Revit, it is important to ensure that release information has been correctly defined prior to transfer.
Releases for each instance are set within the Analytical Members dialog.
Note that the default end release setting for Structural Framing members (including Steel Beams or Steel Bracing) is to have Fixed ends. This may have an effect on the stability of the resulting Analysis and Design model.
Members can be adjusted en-masse within the Autodesk Revit software by the use of selection filter commands.
Group information
Group information cannot be exported from the Revit software and ‘round tripping’ will not be possible if items are held within Groups. (This is due to a restriction within the Autodesk Revit API).
Do not use groups when intending to round trip a model from Revit.
Worksharing and worksets
Tekla Structural Designer has no concept of worksharing or worksets, therefore any collaboration information set within Revit will not be affected in any way. No workset or collaboration information will be written into the CXL format neutral file when exporting models to Tekla Structural Designer.
All supported categories and instances held in worksets will be exported from Revit into Tekla Structural Designer. The collaboration information is not altered by any modifications performed in Tekla Structural Designer. When the model is returned to Revit, the workset information will still be unchanged. (If worksets have been updated in the time between the Export to Tekla Structural Designer and the returning information being merged in Revit, the workset change will also be kept.)
However as Tekla Structural Designer has no information relating to the Revit collaboration commands, any new members created within Tekla Structural Designer will not have workset information defined. These members will be imported into the currently active workset.
Please ensure that when merging models together in Revit that you have full access to all worksets. Please note that any locked worksets or borrowed elements cannot be updated.
Managing ownership
When working within a workshared Revit project, it is critical to ensure that models are synchronised and that no instances are actively checked out by other users during the Create Analytical Model or import / export processes.
To support a more reliable workflow in workshared environments, the Integrator will automatically manage ownership to ensure consistency during data transfer operations.
Firstly, when attempting to import, export, or generate an analytical model, the process will check the status of structural instances. If instances checked out by other users are found, the integrator will stop the operation and log an error with the affected element IDs and corresponding usernames.
Temporary checkout during the Create Analytical model or Import/Export processes
If no checked out instances are detected, the integrator will temporarily check out the instances relevant to the current operation.
This prevents other users from modifying or checking out those instances during the process. Once the operation is complete, the plugin automatically relinquishes these instances.
Ensure users model instant checkout state is preserved.
A list of all instance ID’s currently checked out to the user is then stored. After all unmodified instances are relinquished, the integrator restores the original checkout state using this stored list.
Create Analytical Model / Export vs. Import behavior
Different rules apply for instance selection and checkout depending on whether you're creating an analytical model or importing / exporting data.
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Import processes
If performing an update to an entire model, the Revit integrator checks out all instances in the Revit model.
Selective updates into workshared models now check ownership only for the selected instances, rather than checking ownership of all structural instances in the model.
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Export / Create Analytical model
The integrator checks out only the selected instances, using either the Entire Structure Model or the Selected part of Structural Model option.
This ensures that the exported data remains accurate, is protected from interference by other users during the process, and allows other team members to continue working on unselected areas of the model without disruption.
Integration Filter 'Include' options
The Include options in the Integrator (used to specify what data is imported or exported) are only available during the export process.
For import, these options are enabled as default, as the integrator assumes the entire model may be impacted by imported changes.
The integrator will use the default (enabled) settings for the Opening / Stiffeners, Arcs and Sloping options.
Element collection filtering during the workshare model checks
When performing the internal processes described earlier, the integrator filters the Revit model to include only the elements relevant to a structural project.
The following model categories are included in the integration process:
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Model Categories:
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Floors
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Floor openings
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Structural Columns
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Structural Framing - Beams
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Structural Framing - Bracing
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Structural Trusses
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Walls
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Wall openings
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Annotation Categories:
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Grids
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Levels
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Analytical Categories:
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Analytical Members
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Analytical Panels
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Analytical openings
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All other categories are excluded from this checkout process.
This filtered checkout ensures that:
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Only essential elements are locked during the wizard operation.
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The model remains protected from unintended changes by other users.
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Performance is optimized in larger workshared projects.
Pinning members
The Pin command causes problems within Revit if you are trying to update the model with changes exported from Tekla Structural Designer. Items pinned are essentially locked in location and cannot be relocated or updated by any merge processes.
Use the Pin command with care, and possibly not at all if integrating the model. It can prevent the correct updating of models.
Beam systems
Revit Structural Beam System instances have no equivalent object within Tekla Structural Designer and need to be handled with care.
Although the beam system object itself will not be integrated, the beams held in the system are integrated. The beams will be exported as individual members.
As long as the sections do not change, the beam system will be unaffected on returning results from Tekla Structural Designer back into Revit.
However…
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If one or more beams is changed in section size by the design process, the structural framing instance(s) will be similarly updated in section size on return to Revit. The altered instances will still be retained in the same beam system.
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Any changes to the Beam Type parameter in the Structural Beam System instance will have no effect on the updated instance (it remains at the imported section size).
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Any changes to the layout or justification parameters in the Structural Beam System may also adjust the position of the updated beam but the size cannot be affected.
Changing any adjusted beam size to suit the same type reference as held in the Beam Type parameter will reset the instance. It will now alter to suit any changes made to the Beam Type parameter.
The use of Structural Beam System tags (Annotate → Beam System Symbol) will not show correct information where individual instances have been adjusted by the merge process.
Design Options
The Design Options function in Revit allows you to explore different design options for various parts of your project. Design Options are parts of your model that are separated from the Main Model. The Revit user defines Option Sets, in which multiple Design Options can exist. Revit will only allow one of the Design Options from a set to be shown at any given time, so there is no duplicate geometry on any created view.
Items held in design sets are still part of the main Revit file and will be exported to Tekla Structural Designer as default.
This can easily lead to overlapping or collision of element errors occurring when the Tekla Structural Designer model is validated.
To avoid these potential errors from occurring, we would advise that only one design option be integrated with the Tekla Structural Designer software. To do this, simply access a view showing un-required design options and ensure no Analytical Members or Analytical Panel instances are present.