Unreal Engine walkthroughs real-time architectural visualisation

A still render or a walkthrough film is calculated in advance. Each frame can take a long time to compute, and once it is done it cannot change. This is called offline rendering. In real-time rendering the computer draws each frame as it is shown, many times every second, so the picture can respond to the visitor.

That response is what makes a walkthrough interactive. The visitor turns, walks, opens the floor plan or swaps the flooring, and the next frame shows the result. The condition is that the scene must run fast enough on the machine it is delivered to. That shapes how we model, light and test it.

Tell us the targets at the start. A scene tuned for a powerful PC in a sales gallery is built differently from one that must also run in a headset.

Pixel streaming is the way an Unreal Engine walkthrough reaches a web browser. The walkthrough runs on a remote computer with a graphics card. That computer sends the picture to the visitor's browser as video, and receives their clicks, taps and key presses in return. The visitor installs nothing.

Two things follow. The visitor needs a steady internet connection, because the picture is live video. And each connected visitor uses computing power for as long as they stay, so streaming has a running cost that grows with the number of people using it at once. A link sent to selected buyers needs less capacity than a button on a public website.

A real-time project needs the same drawings as a render, and some decisions that a film does not need. If you already own the computer or the headset, send its specification before we start.

• Plans, sections and elevations: AutoCAD, PDF, or a Revit, SketchUp or 3ds Max model
• Interior layouts, material specifications and furniture selections
• The list of options the visitor can switch
• The delivery targets: PC, touchscreen, VR headset, browser
• The specification of any hardware you already own
• Who will operate it: sales staff, or the buyer alone

It is quoted per project. The main factors are the area to be built, the level of detail, the number of interactive options and the number of delivery targets. A single flat for one touchscreen is a smaller project than a tower with amenities delivered to PC, VR and browser.

Streaming is listed separately in the quote, because hosting is a running cost and the build is a one-time cost. If you have a 3D model from earlier still renders, tell us. It reduces the modelling, although a model made for offline rendering has to be reworked to run in real time. The interactive walkthrough cost guide covers the units.