Parametric Rendering: Why You Don't Have to Model Every Variant
By Facundo Campo, 3D quoting tool developer
In short: Parametric rendering generates the 3D model from dimensions and building rules instead of using hand-drawn models; that's why a single engine can show any combination of a made-to-order product, such as a metal building of any span, length and roof pitch, without anyone modeling each variant.
A metal building with a span from 6 to 40 m (about 20 to 131 ft) in half-meter steps, a length from 6 to 90 m, a roof pitch from 5 to 35 %, three structure types, five cladding options and six sheeting colors for the roof, walls and sliding door produces more combinations than any rendering studio could draw in a lifetime. Parametric rendering solves this the only way possible: it doesn't draw any of them. It generates each part on the fly from the dimensions and the rules the building is built by.
That's the difference that makes a 3D quoting tool viable for made-to-order products. If every variant had to be modeled, it wouldn't exist.
Hand modeling vs parametric
The traditional way to show a product in 3D is to ask a 3D artist for a model: they open their software, draw columns, beams and sheeting, apply materials and deliver a file or an image. That works perfectly for a fixed product. For a made-to-order one, there's a fundamental problem: the model is one building. If the customer wants it 20 m wide instead of 18, someone has to draw it again.
Some configurators try to get around this by modeling a set of variants and stretching parts. What happens is exactly what any steel fabricator would expect: when the building is stretched, the purlins get longer but no new purlins appear, the sheeting distorts, and the sliding door ends up floating or overlapping a column.
The parametric approach flips the logic. Instead of storing a model, you store how it's built: which parts the product has, how they're distributed, how they rest on each other. The 3D is the result of applying those rules to the dimensions the customer chose.
The metal building example: from three numbers to a structure
Take the default building in the metal building and shed configurator: an 18 m span, 30 m length (about 59 × 98 ft), eave at 6 m, 15 % roof pitch, gable roof, truss frames with a maximum spacing of 6 m.
With those numbers, the engine does what a structural engineer would do with a pencil:
- Frames. It divides the length by the maximum spacing and rounds up: 30 m with bays of up to 6 m makes 5 bays, meaning 6 frames, one at each end and four in between.
- Ridge height. Half the span times the pitch: 9 m × 15 % is 1.35 m above the eave. With that, each frame is drawn, with its top and bottom chords.
- Purlins. They're spread across the width with a maximum spacing: an 18 m span gets 13 purlins, one every meter and a half, and each one runs the full 30 m length plus the overhang at the gable ends, resting on the face of the frame.
- Sheeting. The roof is built on top of the purlins, outside the structure, not on its centerline. It sounds like a detail, but if the sheeting sits on the centerline, half of each column's profile pokes through the cladding like scaffolding stuck to the wall.
- Everything else. Longitudinal struts, cross bracing, gable ends, sheeting trims, the sliding door and openings all fit around that structure.
Now the customer says: "What if we make it 32 m long?" The engine doesn't stretch anything. It reapplies the rules: 32 m with bays of up to 6 m makes 6 bays of 5.33 m, so one more frame appears and they're all redistributed at equal spacing. The purlins get longer, the sheeting is recalculated, the cross bracing is repositioned. Nobody drew that building; it exists because the rules exist.
If instead the span goes to 24 m, the frames change, the ridge height rises to 1.80 m and the purlins go to 16. And if the customer chooses a curved roof, the pitch no longer matters: the rise of the arch comes from the span, because that's how an arch is built. A 15 m arch isn't made "at 15 %."
Why this matters to a manufacturer
Beyond the technical side, parametric rendering has concrete business consequences.
- Any size can be shown. You don't have to limit the customer to the five variants that were modeled. If you build in half-meter increments, the quoting tool can offer exactly that.
- Changing one dimension doesn't break the rest. The sliding door stays in place, the sheeting stays supported, the structure stays consistent.
- The price comes from the same parts. If the engine knows there are 7 frames and 13 purlins along 32 m, the pricing logic can use exactly that. What's shown and what's charged can't drift apart. That's the foundation of a reliable 3D quoting tool.
- Production gets something concrete. A configuration that was sold has dimensions and parts, not an interpretation. More in from quote to production.
- Corrections are cheap. If the shop foreman says "the purlin goes differently," the rule is corrected and it's right in every variant at once.
- It's lightweight. No heavy models are downloaded; the geometry is generated on the device. That's why it runs on a phone.
It's not just for metal buildings
The same principle applies to other construction products. In prefab homes, the house is assembled from blocks —bedrooms, bathrooms, kitchen, living room, laundry room— and the walls, roof and porch are generated around them. In horse stalls, the number of stalls, their size and the layout (in a row, facing each other, center aisle) define the walls, doors, tack rooms and the surrounding shed roof. You can try it in the prefab home configurator and the horse stall one.
How Estructuras 3D is built
Estructuras 3D is the parametric rendering engine I, Facundo Campo, built. It runs in the browser, including on phones. Each industry is a module that shares the same engine: lighting, camera, interface, views and layers are already handled. Adding a new product means describing its parts and rules, not building a system from scratch. That's what makes custom development for a manufacturer reasonable in time and cost, as I explain in how much a 3D quoting tool costs.
Some engine decisions only get made by people who know construction: labeling the span "width (span)" so it's understood and learned, telling a truss frame apart from a solid-web frame, putting the sheeting on the outer face. If your product is built by rules, it can be generated by rules. Message me on WhatsApp at +54 9 11 6193-3176 or email facundocampo100@gmail.com and we'll go over it with your catalog in hand, or read how custom 3D quoting software development works.
Frequently asked questions
What is parametric rendering?
It's a 3D model generated from parameters —dimensions and options— by applying building rules, instead of being a hand-drawn model. Every time a parameter changes, the model is regenerated in full and stays consistent.
Does parametric rendering look as good as a handmade render?
For selling a made-to-order product, yes: materials, textures, lighting, day and night mode. A handmade photorealistic render can have more detail in a still image, but it shows only one variant.
Do I need to give my 3D models or drawings to the developer?
It's not necessary. What's needed are the rules: how the parts are distributed and supported, which dimensions and options exist. Drawings help as a reference if you have them.
What technology is it built with?
Estructuras 3D runs in the browser and requires nothing to install.
