Assemblies, Main Parts and Sub-Parts

A HiCAD drawing can contain 2-D and 3-D parts, consisting, in turn, of 2-D graphical elements and 3-D geometry elements. Each of these parts can be a main part or a sub-part, i.e. a part subordinated to a main part. Part groups, so-called assemblies, are used to further structure the drawing. Like the drawing, assemblies and parts are assigned a name that can be used to find and activate them.

HiCAD Part Structure

When are main parts used, and when sub-parts?
When are assemblies used?
What is an assembly?

The part structure also depends on whether you have created the drawing as a part or as an assembly drawing.

When are Main parts used, and when Sub-parts?

Part rule
All parts which are physically a part - which, like a flange or a bolt, can be picked up - are separate components. Reason: If you subsequently want such a part to be moved or reused, you can address it as a connected component and do not, therefore, have to move each line separately. The next two rules determine whether this component becomes a main part or a sub-part.
Main part rule
If a part is independent of other parts of the drawing, it is a main part.
Sub-part rule
All sub-parts are parts that belong to another part in the drawing, e.g. by being bolted on or welded on to this part. For example, holes and bolts always belong to a workpiece, which makes them sub-parts. HiCAD automatically creates these sub-parts for standard products and construction aids etc.

When are Assemblies used?

assemblies are used in 3-D to further structure the drawing.

To define assemblies, you can

create dummy parts to which you then assign the assembly-relevant main and sub-parts or – better
use the special assembly component type. This ensures considerably more efficiency in itemising and identical part search, in bills of materials creation and using HELiOS.

assemblies are dummy parts with isolated points and a special ID. They consist of exactly one main part – the so-called assembly main part - and the sub-parts assigned to this part. All BOM-relevant parts of an assembly are located on one level in the structure; the ID – main part or sub-part – is assigned internally. assemblies can also be nested, i.e. an assembly can contain other assemblies.

A drawing can contain several assemblies, which can also be distinguished in respect of their type - Assembly (general), Welded assembly (Workshop), Bolted assembly (Site), Mullion assembly, Glass assembly, etc.

What is a Main assembly?

A main assembly is a special assembly to which all other assemblies and parts of the drawing are subordinated. Each drawing can contain only one main assembly.

HiCAD allows you to define a 3-D drawing as an assembly drawing immediately upon its creation and to enter it into the HELiOS database if it exists. This ensures considerably more efficiency in referencing, itemising, parts list creation and also in the combined use of the HELiOS PDM system. In the case of a 3-D assembly drawing, a 3-D main assembly to which all subsequently created 3-D assemblies and parts are assigned is automatically created! Main assemblies are used in numerous HiCAD automatic procedures. For example, the product structure of the main assembly, including the subordinate assemblies, is automatically transferred to the HELiOS product structure during itemising and identical part search in steel engineering.
3-D drawings can, however, also be converted subsequently to assembly drawings.

3-D main assemblies are marked in the ICN with the symbol and have the Assembly component type.

In 2-D, the main assembly is created manually by selecting the 2-D Part > Main assembly function. All parts that exist in the drawing at this moment in time are then automatically assigned to this assembly.