Work with assemblies

Tekla Structures
Tekla Structures

Work with assemblies

In Tekla Structures, assembly is a structure that consists of one or several parts or items and possibly other objects, such as bolts, welds and reinforcement. When a part or an item is modeled, Tekla Structures automatically creates an assembly for it. This means that also a loose part or an item has an assembly. When you model more parts in Tekla Structures, you may need to merge several parts into one assembly or join several assemblies together.

Building up assemblies

There are different methods on how to form assemblies in the model and achieve the desired assembly structure. The structure can be flat where the assemblies are on one level, or there can be sub-assemblies on several assembly levels in the assembly structure.

Try out the different ways of composing assembly structures to find out which ones suit your purposes. Note that the different methods to form the assemblies may affect your drawings and reports. We recommend you to test the different outputs early on in the modeling phase to ensure that all the relevant assembly information is included in the needed deliverables, such as production drawings.

If needed, you can later add parts and assemblies to existing assemblies, or otherwise modify the assembly structure to produce the desired outcome.

Additionally, consider the direction how you form the assembly: it might be useful to build the assembly from bottom to top, so that you first create sub-assemblies and then form a higher-level assembly that includes the sub-assemblies.


Concrete cast units are technically considered as assemblies, and they have similar commands available as steel assemblies. In some cases, the assembly commands need to be used for cast units as well.

Hierarchical assemblies

A sub-assembly is an assembly that is added to another assembly to form a hierarchical nested assembly. A hierarchical assembly consists of the highest level (main) assembly, and one or more levels of sub-assemblies under it. Hierarchical assemblies support the manufacturing process of large assemblies, by enabling the combining of assemblies from smaller sub-assemblies into a larger one.

Note that the assembly hierarchy affects the drawing and report outputs. Report and drawing templates need to be made with similar hierarchy as the assembly hierarchy in the model in order to output the data from the correct assembly levels.

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