Tedds 2021 Service Pack 3

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Tekla Tedds for Word
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Not environment-specific

This service pack is required when using the Tedds Engineering Library November 2021 or later.


If you are running a 64-bit version of Windows you will require both updates.

Windows 11

Fixed input controls in calculation user interfaces redrawing incorrectly on Windows 11.

Locally Scoped Variables

The Tedds calculator has been enhanced so that it can support locally scoped variables. The lifetime of a locally scoped variable is limited to the operation which creates the variable. This allows new calculator functions to be implemented which make it easier to write reusable and reliable expressions which do not have unintended side effects.

New ‘Let’ function which assigns values to named variables which can then be used in a calculated expression for which those variables only apply within the scope of the Let function.

In conjunction with the Let function two new complementary functions ‘InitLocalVar’ and ‘InitLocalVars’ have been created which allows you to create local variables within a Let expression.


  • Improved performance If you write the same expression multiple times within another expression the result would have to be calculated multiple times. Let allows you to call the expression by name so that it is only calculated once.
  • Easier to read expressions With the ability to declare named variables which will be used in an expression you can give meaningful context to the purpose of that expression.
  • Easier to write reusable expressions By combining the Let function with expression variables it is easier than ever to write expressions which can be reused in different contexts by defining different values for the expression to use.
  • Easier to write more reliable calculations which do not have unintended side effects. If you write Let expressions which only use local variables you can be confident that your expressions do not have unintended side effects, they will only affect the locally defined variables.

Other Updates

Tedds for Word

[TEDDS-6027]1 - Fixed the User Interface Designer sometimes crashing with a "System argument out of range exception" when changing the Type of an input control from Edit to EditDropList.

[TEDDS-6033]1 - Updated the Tedds Add-In so that the location of the Tedds for Word templates is included as a trusted Microsoft Word location. This prevents Microsoft Word showing an unnecessary security warning when creating new Tedds for Word documents “This document contains fields that can share data with external files and websites. It is important that this file is from a trustworthy source”.

[TEDDS-6166]1 - Fixed the ListAllUnits function not working correctly due to always reporting the error “unable to enumerate units in the unit database”.

[TEDDS-6238]1 - Added a new EvalText function which can calculate a string containing multiple delimited expressions including direct variable assignments (a = …).


[TEDDS-5989]1 - Improved the loading of add-ins for the Tedds calculator so that if a user written custom add-in fails to load it does not stop the system add-ins from loading which previously resulted in an undefined variable error “DListSetFile and SolvCreateSolver” when attempting to calculate any calculation which uses DataLists or the solver functions.


1 This number is an internal reference number and can be quoted to your local Support Department should further information on an item be required.

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