What Is 3D Rendering?

What is rendering in 3D, in plain terms

Think of it in three stages. First, a 3D artist builds a model: a digital version of the building with accurate dimensions, taken from the architect's plans and elevations. Second, the model is given materials and light — brick, glass, timber and paint with real reflectance, a sun at the right angle for the site and the time of day, interior lights, a sky. Third, rendering software calculates how all of that light would bounce around the scene and land on a virtual camera's sensor, pixel by pixel, and writes out the image. That final calculation is the 'render'; the word has spread to cover the whole process and the finished picture.

The software doing the calculating — V-Ray, Corona Renderer, Lumion, Twinmotion, Enscape, Blender's Cycles — simulates physics. That is why a good render looks like a photograph: it was made the way a photograph is made, with light, just inside a computer.

Is 3D photography the same as rendering?

No, although the two are confused constantly. A photograph records light that actually bounced off a real object into a real camera. A render simulates light bouncing off a modelled object into a virtual camera. Photography needs the building to exist; rendering needs only the drawings. That is the whole reason the property industry uses rendering: off-the-plan apartments, display homes not yet built, facade options a client is choosing between, a commercial building being pre-leased two years before completion.

There is a hybrid: a photomontage or verified view, where a modelled building is composited into a real photograph of the site. Councils and courts like it because the context is real; marketers like it because the suburb is recognisable. And there is virtual staging, where furniture is rendered into a photograph of an empty room. Both are rendering applied to photography rather than a replacement for it.

Render, CGI, visualisation, archviz — are they different things?

Mostly labels for the same work. 'Architectural visualisation' (often 'archviz') is the industry's name for the discipline of making images and films of buildings. 'CGI' (computer-generated imagery) is the broader term covering everything from film effects to product shots. A '3D render' or 'render' is one image. 'Rendering' is the process or the service. In Australia there is one important trap: 'rendering' on its own also means cement or acrylic wall rendering — the plaster finish a renderer applies to a brick wall. If you search for a 'rendering company' you will mostly find plasterers. Search for '3D rendering' or 'architectural visualisation' instead.

How does 3D rendering work, step by step

A typical architectural render moves through six stages. Each one is a checkpoint where you, the client, can look and steer. For a worked example of a single home, see the guide to 3D rendering from house plans.

• Brief: you supply plans, elevations, sections and a finishes schedule, and say who the image is for — a buyer, a council, a client.
• Modelling: the building is built in 3D from the drawings in software such as 3ds Max, SketchUp, Revit or ArchiCAD, along with the site, neighbours and landscape.
• Draft render: a near-final image with materials and lighting close to what you need, sent for your feedback — angles, framing and mood are all still adjustable here.
• Materials and lighting: bricks, cladding, glass, stone and paint are matched to samples; the sun is set for the site's latitude and the chosen time; interior lights are placed.
• Revisions: colours, furniture, planting, sky, camera and small design tweaks are adjusted from your mark-ups, across three to four included revision rounds.
• Final render and post-production: the full-resolution image is calculated, then finished in Photoshop — people, cars, colour grading — and delivered as 4K JPEG and TIFF.

When to use 3D rendering

Use a render whenever a decision has to be made about a building that cannot be seen yet. That covers off-the-plan sales and leasing, where buyers and tenants commit from images; development applications and planning permits, where a realistic street view answers objections and satisfies design-review panels; design decisions, where a client chooses between cladding, colours or layouts from side-by-side images rather than samples; investor and tender presentations; and construction marketing — hoardings, brochures, portals, social media — that runs for a year or more before the building is photographable.

It is also used where photography is impractical even for things that exist: large furniture ranges with many finishes, products not yet manufactured, and interiors that would be expensive to style for a shoot.

What a 3D rendered image is used for in property marketing

A residential campaign usually orders an exterior hero, a streetscape, two or three interiors and a furnished 3D floor plan per home or apartment type. A commercial pre-leasing campaign orders the approach view, the lobby, a fitted floor and the amenity. Larger schemes add an aerial or masterplan render and a 30–60 second animation for the display suite and social media. Each image is delivered at a resolution that covers print (brochures, hoardings) and web (portals, Instagram) from one file.

Where to find the prices

Australian studios price per image, and ours are published rather than quoted on request: exteriors from A$445, interiors from A$345. Everything that moves the number, from building size and number of views to verified views, drone composites and volume, is set out on one page, the 3D rendering cost guide, with worked examples. This guide stays with what rendering is and when to use it.

How to tell a good render from a bad one

Look at the light first: a good render has one believable sun, soft shadows where shadows should be soft, and no glow coming from nowhere. Then materials: brick should have depth, glass should reflect the sky and show a little of the interior, timber should not repeat like wallpaper. Then scale: people, cars and furniture should be the right size, and the camera should be at a height a person could stand at unless the image is deliberately aerial. Then context: neighbours, street trees and sky should look like the actual place. Finally, honesty: a render that shows a view the apartment does not have, or planting that will take thirty years to grow, is a liability rather than a sales tool.