Mechanical Design: March 2012

Tuesday, March 6, 2012

Mechanical Design: mechanical structural design

Mechanical Structural Design Reimagined: Scanning, Modelling, and Structural Integrity

Mechanical and structural design has long been the backbone of engineering systems — load paths, frame members, support plates, welds, beam geometry, tolerance stacks. But traditional design workflows often start in abstraction, divorced from the real environment where the system must live.

Today, that approach is changing. With 3D scanning, point-cloud capture, and parametric modelling, engineers can start from reality. Then, using CAD platforms like Inventor, AutoCAD, or SolidWorks, they overlay design intent, simulation, and structural optimization — building designs that not only “look good on paper” but truly fit and perform in the real world.

This post explores how Hamilton By Design bridges the physical and the digital: merging mechanical/structural design with point-cloud modelling to deliver engineered solutions you can trust.

The Traditional Gap: Abstract Design vs Physical Reality

Engineers often begin structural designs by referencing drawings, sketches, or legacy CAD data. The challenge? Everything in the field drifts over time:

Structural frames sag or deform
Weldments distort
Bolt holes shift
Existing steel members corrode or change geometry

When your new design assumes “perfect geometry,” you risk misalignment, interference, or rework once you get to site. Too often, field crews discover that the new structure doesn’t quite fit — because real-world data was never captured.

Enter 3D Scanning and Point-Clouds: Capturing “What Is”

LiDAR scanning or structured-light scanners let you capture millions of spatial points — a point cloud — reflecting the actual existing geometry. This gives you:

Surface profiles, curvature, offsets
Dimensional distortions and wear
Reference baseline for retrofit or extension

You don’t guess or approximate. You measure.

Once you have that point cloud, you can:

Align and register scans from multiple viewpoints
Clean noise, filter redundant points, and segment surfaces
Use surface fitting tools to extract planes, curves, lofts, and solids
Export those as reference geometry or base CAD surfaces

Now your design begins from where things truly are, not where they were intended to be.

Modelling in Inventor, AutoCAD, or SolidWorks: Where Design Takes Shape

With your reference geometry pulled from scan data, you can begin parametric design in any of the major CAD platforms. The specifics differ, but the goals remain consistent:

Parametric constraints & relations: Make the model flexible, with design intent encoded in dimensions, mates, and variables.
Assembly context: Position new parts in context of scanned reference structures — ensure fit, clearances, motion compatibility.
Structural modelling: Define load-bearing members, cross-sectional geometry, weld details, stiffeners, etc.
Simulation readiness: Organize geometry so it can be exported for FEA checks (stress, deflection, vibration) easily.
Manufacturing output: Generate drawings, BOMs, detail sheets, and CNC-ready geometry — all aligned with the true as-built base.

Because your new model is grounded in real surfaces, you avoid frustrating fit clashes and alignment surprises in the shop or field.

Case Workflow: From Scan to Structural Design

Here’s a typical project flow we use at Hamilton By Design:

Project kickoff and scope review
We identify which portions need scanning, which models must interface, critical tolerances, and load requirements.
Field scanning
We scan existing infrastructure (frames, supports, chute linings, foundations) using LiDAR or structured-light scanning tools.
Point-cloud processing
Multiple scans are aligned (registered), noise filtered, unnecessary points removed, and surfaces segmented.
Reverse geometry extraction
Extract planar, curved, lofted surfaces or reference features from the cleaned point cloud. These become your "digital shell."
Parametric modelling overlay
In Inventor / SolidWorks / AutoCAD (depending on client or consortium), we build new structural parts, mates, and assembly constraints referencing the extracted geometry.
Structural validation
From the model, export to FEA (static, modal, thermal as needed) or use embedded simulation features to test stresses, deflection, natural frequencies, and buckling behavior.
Fit & interference checks
Use interference detection tools to confirm that the new parts do not clash with scanned geometry or adjacent systems.
Detailed deliverables
Generate shop drawings, exploded views, weld schedules, and integration documentation — all referencing both new model and original surfaces.
Field alignment & calibration
Use the same scan tools post-installation to verify how closely the build aligns to model, then issue adjustments or corrections.

Structural Design Considerations in This Context

When building mechanical/structural systems over scanned bases, engineers must focus on several extra factors:

1. Tolerances & Fit Bands

Scanned geometry isn’t perfect — there’s noise and minor deviations. It’s critical to decide fit zones (e.g. ±1 mm) rather than forcing rigid adjacency.

2. Stiffness, Loads & Load Path Integrity

Just because something fits doesn’t mean it’s structurally sound. Cross-section sizing, deflection allowances, shear, bending, and frequency response remain critical.

3. Thermal and Differential Expansion

Structures expand and contract differently. Reference geometry must accommodate allowable tolerances — especially in long spans, high-temperature zones, or outdoor environments.

4. Sequencing & Installation Strategy

For assemblies built in place, model planning must consider sequence: which components bolt first, alignment features, jigs, and field adjustability.

5. Service Access & Maintenance

Scan data helps reveal actual proximity of maintenance zones, pipe routes, walkways, and clearance gaps — letting mechanical designers plan access from day one.

Benefits You Can Realize

Drastic reduction in field rework & misfit issues
Improved design confidence, especially around complex or aging structures
Faster project turnaround thanks to upstream validation
Lifecycle data continuity — models evolve as the plant or structure changes
Better stakeholder alignment — visual 3D models overlaid on real backgrounds aid review, assembly, and commissioning

Challenges & Best Practices

Challenge	Mitigation
Noisy point-clouds	Aggressive filtering, segmentation, and conservative surface fitting
Occluded areas	Multiple scans from different angles plus manual measurement
Complex geometry translation	Use hybrid modelling (parametric + freeform) and simplify where necessary
CAD performance	Use region-of-interest extraction and lighter reference geometry
Tolerance management	Use best-fit algorithms and build acceptable deviation bands

Why You Want a Partner Like Hamilton By Design

We combine three core competencies:

Field scanning & data capture by skilled mechanical engineers
Structural & mechanical modelling expertise, from base frame members to integration
Analysis-minded design, ensuring performance and safety, not just fit

When you work with us, you’re not just getting drawings — you’re getting a design environment rooted in reality and engineered for longevity, adaptability, and integration.

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Mechanical Structural Design

Mechanical Structural Design: Bridging Strength, Geometry & Reality

Mechanical structural design sits at the intersection of creativity and rigor. You build frameworks, supports, enclosures, and assemblies — all intended to withstand forces, deflections, fatigue, and real environmental challenges.

Yet too often those designs live in an ideal world: perfect geometry, nominal loads, and no surprises. The true test comes when steel hits the factory floor or is bolted on-site.

At Hamilton By Design, our approach to structural mechanical design is built on three principles:

Integrity — Your design must perform reliably under real load, vibration, and use.
Fit — It should integrate cleanly into the existing environment, with alignment and clearance.
Adaptability — It must evolve over time, not break with minor changes.

In this article, I want to unpack how modern tools — especially 3D modelling and 3D scanning / point cloud integration — help us deliver structural designs that meet all three.

The Core Challenge: Design versus Reality

Let’s face it: real structures diverge from their ideal blueprints over time.

Foundations settle, columns shift, weldments warp
Floors aren’t perfectly level, steel bends under load
Legacy drawings or old CAD models don’t always reflect what’s built

When your new structural design is based just on assumptions or old drawings, you invite field surprises, misfits, and costly rework.

That’s why we prioritize capturing real-world geometry via scanning, then overlaying structural design in full 3D context. The result is a model that doesn’t guess — it fits.

From Scanning to Structural Model: The Workflow

Here’s the process we use at Hamilton By Design when designing structural mechanical systems:

Site Capture / 3D Scanning
Deploy LiDAR or structured-light scanners to capture a detailed point cloud of the physical environment: columns, beams, adjoining structures, surfaces, utilities, and any features that influence the new structure.
Point-Cloud Processing
Align multiple scan views (registration), clean noise and outliers, segment relevant surfaces, and filter to manageable densities.
Reverse Modelling / Surface Extraction
Use the cleaned point cloud to extract planes, curves, lofted surfaces, and boundary edges. These become reference geometry.
Parametric 3D Design
In tools like Inventor, AutoCAD, or SolidWorks, we construct the structural model with full parametric intent: beams, gussets, stiffeners, connections, plates — all related and constrained.
Structural Validation & Simulation
We perform stress, deflection, vibration, buckling, fatigue, and thermal analysis as required. Because the model is based on scanned geometry, the simulations reflect realistic boundary and interface conditions.
Fit Checks & Clash Detection
Use model-based interference tools to ensure your new structural elements don’t conflict with scanned or existing plant elements.
Detailed Documentation & Fabrication Outputs
Generate shop drawings, cutting lists, connection details, and annotations — all geometrically consistent with the 3D model and the real-world scan.
Field Verification & Calibration
After installation, we can rescan to check alignment, deflection, or deviations — closing the feedback loop.

Why This Approach Elevates Structural Design

Benefit	Structural / Mechanical Outcome
Precision Fit	You eliminate guesswork; new frames, supports, and attachments land exactly where they should.
Reduced Rework	Clashes, misalignment, and tolerance errors are detected early in model space.
Design Confidence	Real geometry → real constraints → fewer surprises.
Easier Evolution	Models can adapt to changes, additions, or refurbishment without starting over.
Lifecycle Data Integrity	Your model becomes the accurate as-built record.

This is mechanical structural design elevated: not just analyzing ideal geometry, but designing in context with the built world.

Structural Considerations in Scanned Context

When designing structures on top of scanned environments, you must pay attention to several nuance areas:

1. Tolerancing & Fit Bands

Scan data contains noise and deviation. Rather than expecting perfect surfaces, we build tolerance bands (± mm or fraction of a mm) into mating surfaces to absorb variation.

2. Load Path Clarity

Even when geometry comes from scan, the structural logic must remain clear. We trace load paths through beams, gussets, welds, and supports such that under load, the system acts predictably — not in chaotic ways.

3. Connections & Joints

Bolted connections, weld transitions, stiffeners, and gussets often end up misdesigned if they ignore actual geometry. When you see existing conditions via scan, your connection design accounts for real misalignments and dimensional variation.

4. Deformation & Warpage

Existing structures may already be stressed or deformed. When adding new loads, the superposition must consider the current structural state. Scanned geometry gives you that baseline shape rather than the ideal.

5. Access & Maintenance Clearance

Scanned environments reveal actual fixed obstructions, walkways, pipe bundles, utilities. That lets design place access panels, maintenance zones, and service clearance intelligently, not hypothetically.

Real-World Use Cases

Mine infrastructure retrofits — adding structural supports, walkways or platforms inside existing plants, where geometry is complex and constrained.
Conveyor frame extensions — designing frames that must fuse into existing supports, often with misalignment or drift.
Machine foundation and base frame upgrades — scanning existing foundations and anchoring new structures with perfect integration.
Plant upgrade and expansion — new structural modules designed to wrap around existing facility structures captured via scan.

In each case, the scan + structural model approach pays dividends in accuracy, cost avoidance, and reduced field surprises.

How Hamilton By Design Executes Structural Precision

We combine field scanning expertise, structural engineering skill, and parametric modelling agility. Key principles in our delivery:

Engineering-first scanning — we don’t just scan; we scan with purpose, knowing which surfaces, planes, and features matter to the structure.
Controlled modelling — avoid over modeling desktops — focus on key load bearing and interface geometry.
Simulation-informed design — we embed analysis early, not as an afterthought.
Clean deliverables — models, drawings, and scan references that are readable, keyed, and actionable.

With that, your mechanical structural design isn’t just viable — it’s resilient, logical, and built to fit.

www.hamiltonbydesign.com.au