“Fruedela” is a parametric design assistant for thin-shell concrete structures. Built in Grasshopper with Karamba3D for live structural analysis, Fruedela lets students slide geometric parameters and immediately see both the structural response and how their design ranks against a built historical benchmark. The goal is to make Candela’s structural intuition accessible to a new generation of designers.
Intended users
Structural engineering students learning shell behavior & early-career architects exploring thin-shelled structural forms. This isn’t a final design tool, it’s an early-stage exploratory design assistant where users can play with proportions and immediately see how their choices affect structural performance.
Need you’re trying to provide a solution or support for
Thin-shelled structural behavior doesn’t follow the structural intuition engineering and architecture students have learned from beams and columns. A shell twice as thick isn’t twice as good, and a shell with sharper curvature can be lighter and stiffer. Without specific shell training, designers tend to default to one of two failure modes: overly conservative designs that lose the elegance of the form, or formally elegant designs that fail under their design loads.
What students need is fast, visual feedback on three questions:
- Is the shell safe under self-weight loading conditions?
- Is the shell efficient with material?
- How does the shell compare to a shell that’s known to work?
No widely available tool for students helps them assess these questions in real time against a built historical benchmark. Fruedela closes this gap by letting designers slide a few geometric parameters and immediately see both the structural response and how their design ranks against Candela’s Los Manantiales (see below).
Inputs
- Outer radius (5 to 30 m): Distance from center to each of the eight perimeter tips
- Tip height (2 to 15 m): Height of the eight outer tips above the ground
- Shell thickness (2 - 15 cm)
- V-beam depth (30 to 100 cm): depth of the V-beam groin stiffeners
- V-beam width (6 to 20 cm): wall thickness of the V-beam cross-sectio
- Mesh density (8 - 30)
Constants: concrete material properties (C30/37), pinned support conditions at the four ground groin points, self-weight load only, and the four-hypar / eight-tip Los Manantiales topology with V-beam edge stiffeners along all eight groin lines.
Underlying logic of the model you’ll implement
The tool generates a four-hypar groined vault parametrically, replicating the Los Manantiales geometry. Four hyperbolic paraboloids are arranged radially around a central axis, intersecting to form an eight-tipped, eight-supported shell with a central peak that emerges from the intersection of the four surfaces. This exploits the doubly-ruled property of hypars: every point on each surface lies on two straight lines, which is the geometric reason Candela was able to build these shells with straight wooden formwork.
Along the eight groin lines where adjacent hypars meet, the tool adds V-beam stiffeners modeled as trapezoidal beam cross-sections. These represent the reinforced-concrete V-beams Candela used in his groined vaults to absorb stress concentrations at the supports, allowing the shell itself to remain only 4 cm thick.
The full assembly (shell + V-beams) is meshed, assigned concrete material and shell-element properties, supported at the eight ground points, and analyzed under self-weight using Karamba3D's second-order shell analysis. The analysis produces displacement, mass, principal stresses, and per-face utilization data. A comparative dashboard then converts these raw outputs into the metrics that actually matter for shell elegance: span-to-deflection ratio (L/Δ), slenderness ratio (L/t), mass per surface area, and a stress index based on the 95th-percentile Von Mises utilization. Each metric is shown side-by-side with Los Manantiales' known values as a benchmark.
Outputs
- Live 3D visualization of the shell, colored by stress utilization, updating in real time as inputs change. Helps to visualize which parts of the structure are contributing the most.
- A comparative dashboard showing the four elegance metrics alongside Los Manantiales’ known values. Helps students to see how their proportions sit relative to Candela’s design.
- A pass/marginal/fail verdict identifying whether the current design falls within “Candela-elegant”, “structurally conservative”, “overstressed”, or “failing serviceability” ranges. Helps translate raw numbers into actionable guidance for users who may not have shell-design intuition
Timeline and Scope:
- Week 1: Geometry and Analysis Pipeline:
- Build the parametric four-hypar Los Manantiales generator (eight tips, eight shared ground supports), integrate Karamba3D for shell analysis, and produce a working utilization color map with live feedback as sliders change. This is the minimum viable working tool.
- Week 2: Polish and Core Additions:
- V-beam groin stiffeners modeled as Karamba beam elements along the eight groin lines, comparative dashboard with Candela benchmarks displayed live in the viewport, verdict logic translating metrics into a plain-language design status, input bounds with validation panels, internal canvas labeling and grouping, Notion documentation, and demo video.
In addition, if I have extra time, I would like to add the following features. I have restrained these features from the scope above to avoid excessive scope creep on this assignment.
- V-beam on/off toggle to show the contribution of edge stiffeners
- Tapered V-beam cross-section matching Candela's actual 60 cm-to-120 cm depth taper
- Preset library loading the dimensions of built Candela works (Cosmic Rays Pavilion, Bacardi Bottling Plant)
- Principal stress streamlines visualizing how the shell channels load
- Multiple shell typologies (single saddle, umbrella shell, etc.)
- Embodied carbon score multiplying concrete volume by carbon intensity
- Deformation animation showing exaggerated shell sag
- Animated principal stress flow particles
- Ladybug daylight analysis beneath the shell. Analyzing daylight penetration, solar exposure, and shadow casting.
- Cost estimation based on concrete volume and formwork area
- Thickness optimization visualization via Galapagos with Pareto frontier diagrams
- "Force Literacy" labels for compression zones, tension zones, anticlastic curvature, and membrane action
- Failure mode visualization using Karamba buckling analysis