Category Archives: Tekla API

A series of blog posts exploring the Tekla API.  Code examples, explanations and (where relevant) videos will be provided.

Select Bolts From Tekla Model Based on its Tolerance using WPF (Tekla Open API) + Code Snippets + Video Demo

Select bolts depending on their tolerance
It’s not easy to find which bolt has a tolerance of 10 when you have 1000s of them in your model.
You can really only do that type of thing with a tool.

This is a repost from our sister site – I needn’t repeat it here, but it’s something that I’ve worked on, and which we hope to utilize to a greater degree when working with Tekla. Anyways, you can get the full blog post if you click this link here. Thank you for stopping by.

Video Demonstration of Bolt Selector Tool

Select Bolts From Tekla Model Based on its Tolerance using WPF (Tekla Open API) Video Demo from Tek1 on Vimeo.

How to Programmatically Select Objects in the Model (Tekla Open API)

Return a selection of objects back to the user.
We can easily select objects as an input – objects which was can iterate over and apply a series of operations or checks out. But how do we return a selection of objects back to the user?

Background: What are we trying to do?

We have programmatically identified some model objects that we want to select in the model – to attract attention to the user and to allow her to easily identify all such objects. In this particular case we will be creating some beams. And then, we will select those beams in the model. Here is a code snippet to get you started:


How to Get Parallel Grid Line Points (Tekla Open API)

All Gridlines Dimensioned
When marked to all grid lines, this makes it easy for the folks on the floor to mark out. Don’t make it hard for them!


What is the task at hand?

So I get some phone calls the other day – people complaining. They want changes. Yet again! Why  can’t these people make up their minds! That means I have to get off Facebook, go back to my code – which I hopefully haven’t forgotten, and I have to try and  make their changes fit in, with the least amount of trouble.

What did they want this time?

They wanted to dimension bolts not just to one grid line, but to every single one. Ok that’s fine. How am I going to select all parallel gridlines, given an input of just one gridline?

  1. First I need the input Gridline. This is given. We have the input gridline because we’ve asked the user to select a relevant gridline.
  2. We need to get the actual grid, using that grid line.
  3. We need to get all pertinent gridlines using the grid – we want to get only the gridlines that are parallel with our originally selected gridline.
  4. Using those filtered gridline points, we need to extract out a pertinent reference point and add that to the set of points used to create the dimensions.

1. The Input Gridline

  • This has been obtained by selection.

2. Getting the Actual Grid



3. Getting Pertinent Gridlines

Now we extract the relevant points given the above information.

This is the final result:

4. Create the dimensions

We’ve got the bolt dimension (previous post). We have some grid line dimensions (see above code). Add the above points to the bolt positions and then create those dimensions as outlined in the previous post. Voila! We are finished! Now back to WoW!

Copying From Object To Object – Tekla Open API (Code Snippets + Video)

An example of us copying a column from one object, to the rest – to the rest of the beams.

What is the task at hand? We want to make the Copy Object To Object command more efficient

There is a nifty little command – little oft used in Tekla. The “Copy Object To Object” command. It’s handy, but it could be made better: all the model objects have to be selected individually. That can be a little bit of a pain. In this lesson we will create some code, using the Open API, to allow users to select multiple objects (all at once) by which the copy object to object command can be applied to.

Where is the pertinent Call in the API? I’d prefer this type of thing to be a method on the relevant ModelObject. But it’s static method in the Operation class. Here is the hello world example, straight from the documentation:

Copying Object to Object – Hello World Example:

This is fantastic! Now let us outline what we want the command to do:

What do we want our command to do?

  1. We want the user to select an object (or group of objects).
  2. We then want the user to select a “source” object.
  3. We want the user to then select all objects to copy to.
  4. The program should then use the parent object as a source, and use that as a reference to copy everything selected in step #1 to all the objects selected in step #3.
1. Ask the user to select a bunch of model objects – The objects to copy

We can use the Picker class, located in the Tekla.Structures.Model.UI namespace. And there is a handy object which thankfully has been exposed: PickObjects(Picker.PickObjectsEnum, String). This returns a ModelObjectEnumerator which we can iterate over.

2. Ask the user to select the source object:

You can get the source object in the same manner as the above code – except you would use the PickObject method instead of the PickObjects (plural) method.

3. Ask the user to select the objects to copy to:

We can use the same method used in step 1.

4. Copy from Object To Object

The rest is as easy as A-B-C:

5. Finally, we want to Redraw Views after the Copying Operation has completed

Video demonstration

…That’s all folks. Hope you learned something!

Dimensioning Bolts in a Tekla Drawing – Tekla Open API – (Demo + Code snippets)

The picker can’t pick multiple items.

We want to create a little drawing plug-in

What we want to do is to select and dimension all the bolts to a particular grid line. Here’s how it should work:

* The user selects a group of bolts.
* The user selects a gridline.
* Dimensions are drawn from the Bolts to the Gridline.

But quelle surprise – the Tekla API doesn’t expose an object which can select or pick multiple drawing objects.

What are some solutions around this problem?

We’ll we’re gonna have to be a little creative. Thankfully, Trimble have exposed the ability to programmatically obtain drawing objects. Given these objects we need to somehow filter out the stuff we want to dimension. Here are some possible ways:

  • We could provide a Control where we can choose and filter what objects we want to dimension, after reading/seeing it’s properties in some type of user interface (you could have a WPF application and use its fancy data binding ability + MVVM pattern + Command objects working with Service layers and Messengers) – but that would require considerable effort.
    You could just select everything individually. But that would take forever.
  • You could extend the PickerInputWithinAView abstract method to allow you to select multiple objects.
    Or you could find a way to easily filter it all. And I think I’ve found a way.
  • Deep in the annals of the Tekla API Reference Guide, I found that the Picker type exposes the PickTwoPoints method. And if we can pick two points, then we can certainly filter our selections.

Issues In the Algorithm We Need to Address

  1. User picks two points.
  2. User picks a gridline
  3. We then filter all bolts within the bounding box of the original two picked points, and we create dimensions to the appropriate gridline. We need to understand the Drawing API.
  4. We also need to know about saving and reverting transformation planes.
  5. This is the hello world version of what we are trying to do, but perhaps on a scale that is a little more grand. We need some basic code on how to create dimensions.

How to Programmatically Pick Two Points

How to programmatically select a grid line

Understanding the Tekla Drawing API

Please refer to the below diagram.

Tekla Drawing API structure
An Explanation of how the Tekla API categorises its objects.

The things that you see in the drawing, are not exactly what you can see on the model. They are drawing representations of what you see in the model. If you want specific geometry based information concerning what you see in the drawing you must:

1. First get the drawing object (i.e. the drawing representation you see as a Bolt in the drawing).
2. Then you must get that same Bolt in the model.
3. You must then inquire in the model about the particular attributes or positional properties of that bolt – which is represented as a bolt in the drawing.
4. You must also bear in mind that Views etc have their own coordinate system. So if you may need to translate any differences which exist in the model to the local coordinate system of the particular view you are using. You can set and retrieve the transformation plane like so:

How to Save And Revert Transformation Planes

5. So if you need to create some dimensions, the exact lengths etc must be derived by querying the pertinent model object representations of what you see in the drawing.

How to Create some Dimensions

Dimesnions Explained
The diagram provides a handy summary and visual representation of the parameters you need to pass in when creating a set of dimensions using the Tekla Open API.

How to get the drawing objects (in this case bolts) and programmatically filter them out

A Primer on how the Tekla.Structures.Drawing namespace is structured

Firstly you have a Drawing class. There are many types of drawing sub-classes:

* AssemblyDrawing
* CastUnitDrawing
* GADrawing
* MultiDrawing
* SinglePartDrawing

Within each drawing is what is called the ConatinerView. A sheet is a container view. A container view is simply – if I were to use an everyday metaphor if you were grocery shopping – a bag which you can use to put: (i) other bags or (ii) shopping items inside. In order to get the ContainerView object, you can use the Drawing.GetSheet method – and you will be returned a ContainerView object.

Inside a container view you can typically:

* GetObjects()
* Or you can GetAllViews
* Or you can GetAllObjects of a certain type.

And within the container view, using some of the above methods you can get all sorts of DrawingObjects:

* DetailMark
* Dimensions etc
* Drawing representations of ModelObjects – like: Bolts, Connections, Grids, Gridlines, Parts, Welds etc.

Put all the elements together

If you put all the elements together, you can create some powerful little Plugins. I can’t post the full code because my boss will murder me, so I’ve done my best to teach you the key elements so you can create something powerful yourselves.

The Demo

Here is the video demonstrating it in action:

Tekla Open API Plugin – Dimensioning all selected bolts from Tek1 on Vimeo.

Thank you for watching!

I hope you learned something from this post.

How to programmatically insert Reference Models into Tekla (Tekla Open API)

Wouldn’t it be handy if we could programmatically insert reference models into Tekla? Well you can now do so quite easily.

Here is the code which does the hard work. (You will of course add the appropriate references and directives):

And if you want to see a video demonstration, here it is:

Inserting XRefs into Tekla as Reference Models from Tek1 on Vimeo.

Pick First Selection in the Tekla API (Tekla Open API)

The AutoCAD .net/ObjectARX APIs have a handy feature all the pick first selection. This means that prior to running a command, the user is able to select some objects in the model. The command is then able to use these objects. The question is, how to obtain a selection of objects using the Tekla API – prior to running your plug-in?

It’s really simple (if you already know how):

And that’s all it is! Hope this helps.

How to Set Up a Tekla API Project (Tekla API Application)

Work faster with the Tekla API

The object of a Tekla Application is to ensure that things go smoothly on the construction site. You can see the organised chaos that is here. Avoid the real chaos. Plan ahead and raw well. 

For the newbie this post shows how to set up a Tekla Project.

Let us assume that you are creating a WPF desktop Application.

  1. Go to Visual Studio.
  2. Create a new WPF project.

Follow this gif:

Setting up a Tekla Project
How to Set up a Tekla WPF Application
  1. Next you need to add references to Tekla DLLs. They are contained at this location on my PC. C:\Program Files\Tekla Structures\19.1\nt\bin\plugins\ .They may be in a different version on yours.

Follow this Gif:

Adding Tekla References

Shows how to add references to a Tekla API WPF Project.

  1. The fourth and final step is to add directives and to then get coding.

Some common directives and aliases that I use:


I hope this post helps you!

Showing an Assembly in the Model via a Tekla Drawing (Part II) Tekla Open API + Code snippets

We are revisiting a post I made earlier.

Here’s the problem. You are viewing a Tekla drawing. But you have no idea what you are looking at, or where it is. This macro will take you to that very assembly in the model. It’s actually quite handy. And here is the previous post where I made allusion to the facility (you’ll find a video demonstrating its use):

Showing an Assembly in the Model via a Tekla Drawing (Part I) – Tekla Open API Plugin

This post marks the release of the code which does the job! Enjoy!

AutoCAD-Tekla Interoperability

Tekla – AutoCAD Interoperability Tool

Tekla licenses are pricey. About $30k + maintenance per license. What if I told you that you needed 30-50% less licenses than you currently hold. That’s a huge cost saving, isn’t it?

If you only need 5 licenses (as opposed to 10), then you’ve saved $150k instantly, plus maintenance.

AutoCAD licenses are significantly cheaper.

But if only the work you did in AutoCAD could be transferred into Tekla? That would save you some licenses. That’s just what I’ve done here in my latest project. Now a significant portion of any modelling job can be done in AutoCAD and simply imported into Tekla.

You can check it out here:

Tekla – Autocad Interop. from Tek1 on Vimeo.

Human Resources Problem

Interoperability will also help improve the quality of your work: it’s tough finding people who are highly skilled in Tekla. What if I told you that you could use an AutoCAD draftsperson instead of someone well versed in Tekla, to do the same job? Now you have a potentially infinite pool of candidates to draw from.

Interested In more?

I’d love to be able to help. Just call or email us.