Direct Answer
Both are professional-grade 3D steel detailing platforms, but they serve different strengths. Tekla Structures is the global industry standard for complex, large, and multi-discipline projects — especially those requiring IFC export and BIM coordination. SDS/2 is strong for repetitive commercial and industrial structures and has excellent automated connection design. The right choice depends on project complexity and the detailer's existing expertise.
Full Explanation
Tekla Structures (by Trimble) dominates complex work: multi-story, long-span, heavy industrial, and projects requiring full BIM integration with MEP. Its IFC export is industry-leading, and it integrates with Navisworks, Revit, and common CDEs. SDS/2 (by Design Data) excels at standard connection automation — it can design and detail many connection types without manual input, reducing detailing time on repetitive structures. SDS/2 also has a strong AISC connection library. Most US fabrication shops have at least one detailer familiar with each.
What This Means for Your Shop
If your project requires BIM coordination or IFC model exchange with an architect or GC, insist on Tekla. If your project is a repetitive pre-engineered-style structure with standard connections, SDS/2 may deliver faster. Ask your detailer which platform they use for similar projects.
Common Mistakes
Assuming one platform is universally better. The detailer's proficiency matters more than the platform. A Tekla expert will outperform an SDS/2 novice on any project type, and vice versa.
Recommended Process
When engaging a detailer, ask what platform they use and why they use it for this project type. Request examples of completed projects on that platform. Verify the platform can export the file formats your GC or downstream contractors require.