SOLIDWORKS Structure System: Primary vs Secondary Members

Introduced in 2019, Structure System is one of the newer tools available within SOLIDWORKS. An advanced extension to the long-existing functionality within Weldments, Structure System provides an alternate workflow to create complex structures, with greater ease and efficiency. Operating in a unique manner when compared to most other features or commands, I tend to think of the structure system feature as a “mode”.  When initiated, we enter the ability to implement Primary and Secondary members. Exiting the structure system prompts a final stage in the mode-like feature, the corner management tool.

In this article, we will review the difference between the two member types and discuss some items to keep in mind during creation.

Understanding the Member Types

By default, primary members must be created before it’s possible to insert any secondary member. Following the SOLIDWORKS enhanced tooltip for each member type, the implication is that primary members are intended for the creation of the main support elements. Secondary Members can then be used for creating of all elements existing between two or more other members. Don’t overthink this!

Control the use of “Primary Members”

Even though it is possible to generate many members or elements of a structure system using primary members, keep it simple by limiting them to the “primary load bearing elements”, as suggested. Looking at a large building type structure for example, it’s likely that primary members are only needed to create the vertical upright elements as seen below. This remains true, even if the profile selections will stay the same for many of the secondary members. Following this simple rule limits the requirement to create complex sketches when creating the primary members, allowing SOLIDWORKS to do the heavy lifting during creation of the secondary members.

SOLIDWORKS Structure Primary Member Operation

Considerations

While thinking forward is an important factor during any creation process, not everything can be anticipated. After all, isn’t that the reason why we use CAD tools to develop and refine our ideas. Fortunately, like all tools within SOLIDWORKS, Structure Systems also allows for changes to be made at any time. That said, while refinement is sometimes unavoidable, thinking ahead on design intent and anticipating subsequent steps during Structure System creation, will more than likely prove beneficial. It can work in your favour to save time and reduce the ripple effects associated with changes.

Keep in mind factors such as:

• Member Profile selections
• Member Rotation
• Pierce points
• Contact between members
• Corner Management Conditions