Technical and mathematical diagrams representing computational design

Generative Design in BIM: Optimising Before You Draw

Spetia Engineering R&D·January 12, 2026·9 min read
Key takeaways
  • 01Generative design uses algorithms to explore thousands of design options against defined goals (cost, performance, buildability) and surface the best.
  • 02It shifts effort upstream: you optimise the scheme before committing to detailed drawings, when changes are cheap.
  • 03It augments engineers, not replaces them — humans set the goals and constraints and judge the trade-offs.
  • 04Applied to layouts, structure, and MEP routing, it directly serves the cost- and time-reduction goals of a project.

Traditional design converges on one or two options early, then spends months detailing them — which means you commit to a scheme before you really know if it’s the best one. Generative design inverts this. It lets algorithms rapidly explore thousands of variations against your actual objectives, so the scheme you take forward is genuinely optimised, not just the first one that worked.

What generative design actually is

You define the goals (minimise cost, maximise usable area, hit a structural or energy target), the constraints (site, code, clearances), and the variables (grid, orientation, member sizes, routing). The system then generates and evaluates many candidate designs, presenting the trade-offs so an engineer can choose intelligently. It’s optimisation with the human setting the terms and making the call.

Where it applies in engineering

  • Plant and facility layout: exploring equipment arrangements for flow, footprint, and conveying efficiency.
  • Structural systems: testing grids and member schemes against material cost and performance.
  • MEP routing: finding the least-conflict, most-efficient service routes.
  • Massing and site: balancing area, daylight, and cost early in a building project.

Better decisions, earlier

Generative design is one of the ways Spetia Engineering turns R&D into client value — helping you commit to an optimised scheme early, which is where the biggest cost and schedule savings on any project are actually won.

Frequently asked questions

What is generative design?+
Generative design uses algorithms to automatically generate and evaluate many design options against defined objectives (such as cost, performance, or buildability) and constraints. Rather than manually developing one or two schemes, engineers set the goals and the system explores thousands of possibilities, presenting the trade-offs so the best option can be chosen.
Does generative design replace engineers?+
No. Engineers define the objectives, constraints, and variables, and they judge the trade-offs and select the final design. Generative design automates the tireless exploration of options; engineering judgment sets the terms and makes the decisions. It augments engineers rather than replacing them.
How does generative design save cost?+
It front-loads optimisation into the earliest project phase, when changes are cheap, so you commit to a genuinely optimised scheme rather than the first workable one. Because the cost of change rises steeply as a project progresses, optimising the scheme early captures the largest available savings.