Weldments vs Structure Systems
The Structure Systems feature has great potential to replace weldments in most situations. Even small numbers of members are quick to set up and provide more modelling flexibility. So why should you think about using Structure Systems:
- Members can use different profile types and sizes seamlessly in one feature.
- The path of the members can be defined using planes, points, surfaces, and lines. This provides the freedom to choose how to define your weldment. This is also be a faster and more intuitive way than through 3D sketches.
- Members will trim automatically where they intersect, with only occasional manipulation needed. This makes a feature tree full of manual trimming features a thing of the past.
- Manipulating a large weldment structure is easier than ever as all members are stored in one feature. Locating a member’s definition and corners takes just a couple of intuitive clicks. Important parameters like the profile type and pierce location can be changed for an individual, several or all members at once. Large structures are therefore still manageable and easy to edit.
To show its potential, we shall use the above crane to demonstrate the tips and tricks. Let us go through what you can expect when setting up a Structure System.
Setting up Your Profiles
The first step is ensuring you have your profiles setup correctly. Structure Systems has a prerequisite that the profiles need to be configured (the profile sizes are stored as configurations rather than separate part files). Since 2019, the weldment profiles provided with SOLIDWORKS are configured. However, if you are still using the profiles from 2018 and before, they will be non-configured. Make sure you have set yourself up with the correct type of profile before starting. See our blog on how to create a configured profile.
Structural Systems requires configured profiles that are best setup using a design table.
To start, the Structure System feature is selected from its own tab. A sub-environment like when starting a sketch is entered. Primary members can then be defined, followed by secondary members. A ‘confirmation corner’ icon is available to exit the sub-environment. Note that if members have been defined before exiting, you will first enter the second part of the feature, corner management. This will be gone over later.
‘Structure System’ will enter a sub-environment where members can then be defined.
‘Exit Structure System’ or the confirmation corner will initially exit to the corner management tool.
Primary members can be defined through using planes, sketch segments, points, and intersections. Primary members therefore rely on reference geometry for their path. Unlike Weldments, the members do not need to be parallel or consecutive to each other. They may also be defined using splines and can use different profiles.
4 primary member types are possible. ‘path segment member’ (above) uses sketch lines like weldments.
‘Ref Plan Member’ definition requires two planes to define the start and end of the profile, and then two intersecting planes to create an axis. If appropriate, multiple planes can be used to create multiple members.
Secondary members use primary members to define their positioning to quickly build up supporting weldments. The distance along / length ratio of the primary member is used to define them. Note that initial selections are rough distances and then the values should be defined afterwards. Pre-created planes can also be used for positioning. Finally, these members can even use primary members from other Structure System features, making it easier than ever to build up large structures piece by piece.
Secondary members are defined in-between primary members and use their length for definition.
Once all members have been defined and you exit the feature, the corner management will be processed. All corners will be automatically defined but can be overridden. The corners are split into type depending on their complexity: simple, two-member, and complex.
Simple corners occur when no trim order is needed as only one member end is present. The trim type can use planar or body trim, with full contact or first contact possible.
A simple corner with full contact planar trim.
Two member corners occur when two member ends meet. Trim types available are mitre, planar, and body trim, with the trim order editable.
A two-member mitre trim corner.
Complex corners occur when more than two members meet. A trim tool member uses this member to cut all others, trim orders can then be set for remaining members, and ‘planar trim’ can be used to trim via face/plane as well.
A complex corner with three members.
Managing the Structure System Feature
The Structure System feature will generate a relatively large folder system, but it can be broken down and managed easily, let’s go through each component.
First off is the Structure System Grid. This is really an internal feature and is a result of all the hard work done when defining the members. Each member defines a sketch line for its path, these lines are then combined to build up a 3D sketch without ever needing to define 3D relationships. This is parametrically linked so that if members are modified, even the pierce point or any offsets, this sketch will also change.
Underneath this are the created members, separated into unique profile folders. Once outside the Structure System feature environment, each folder/member can be edited individually to modify its parameters through just a couple of clicks. Whereas in weldments, locating the member could be arduous due to large numbers of weldment features and groups, and changing a profile would change all members profiles. This is also where members are deleted by right clicking the top-level profile folder/member and choosing delete.
The last folder is for the corner management. One of Structure System’s main advantages is all corners are trimmed automatically between all profiles. Like structural members, the corners can be modified individually or as a group. The easiest way is to edit the sub-folder the corner belongs to and then find the corner from the graphics area.
Graphics Manipulator & Pierce Point
A new feature released in 2021 is that the profile can be manipulated dynamically if the initial profile alignment is incorrect and no axes are available to align it with. Simply drag from the triad to position the profile in the desired orientation. It can also be useful to visually position the profile roughly before using the ‘profile alignment’ option to align exactly.
Member profiles can be manipulated easily with a triad.
A final feature called ‘pierce point’ on the Structure System tab pre-defines pierce locations on the profiles. This allows pierce locations to be easily identified and selected during member definition. It is made specifically for, but is not limited to, I-beams. This saves the sometimes-awkward selection process that requires locating and zooming in on the profile and selecting through geometric entities. To set these, simply open the profile, select the pierce point feature, and assign a vertex/ sketch point to its correct reference. These will then be available to select when using the profile.
Pierce Points can be pre-defined within a profile to make easier selection later.
Building up Your Model
Once the Structure System has been finished, additional features can be added to the framework. During this process it may become clear that the Structure System needs refining or to be iterated. A few tips to help this process are:
- Bodies and Structure Systems can be both patterned to save the trouble of repeating work. Keep this in mind from the onset so that you can recognise patternable structures initially and create only unique members.
- The corner management folder is a process-heavy feature and suppressing this can speed up the rebuild time significantly. Use this to your advantage when refining the initial framework sketches and members. It will allow you to work in and out of the structure system feature quickly when creating new members without having to wait for all corners to be built. Just remember to unsuppress afterwards once complete.
- A second Structure Systems feature can still be trimmed by the first Structural System feature members. Therefore, the framework can be split into sections to ensure the feature is manageable while still generating automatic corner treatment.
Structure Systems recognises the capability of weldments and builds more freedom and more functionality into it. Weldments will still be helpful for smaller models that consist of the same profiles, but structural systems can provide a faster and more friendly workflow for larger or more complex models. The age of weldments is coming to an end, long live Structure Systems!