Global Illumination, the foundation of realistic lighting in 3D visualization, has always been a demanding and challenging issue for rendering engines to solve. Direct use of UE4's pathtracing is a great yet not perfect solution, since UE4 uses BruteForce and has some problems to be solved before it can be used as a renderer.
Craving to create a real-time rendering tool which allows 3D designers from architecture, landscape, and interior design industries to have both a precise preview and realistic output of the visualization project, the D5 Team decided to make some in-depth improvements on the ray-tracing tech that comes with UE4.
After a long-term experiment that went from DXR to FallbackLayer, and then to Optix, from random sampling to discrete space sampling, they finally came up with a solution containing a combo of techs that help D5 Render to be such a tool at designers' disposal.
To make up for UE4's lack of enough samples, the D5 Team used discrete sampling, with which the scene would get rid of remarkable noises while the graphics card could handle it with ease.
The cached low-frequency statistics get GI in D5 to precisely cast soft shadows, thus adding a ton of realism into the render.
UE4 has been using this technology to replace some of the computation. So does D5 Render. That Gbuffer allows rays to be emitted as required saves the time and cost of primary rays emitting, thus making a good integration of ray-tracing and pipelines.
Advanced Sky Light to produce better shades
D5 Render, underlied by RTX that's good at ray intersection, introduced Sky Light based on that of UE4 and took a step further by adding a denoising algorithm and adjusting ray-wise strategies, so that any HDRI imported into D5 could have gorgeous performance and produce precise and clean shades.
Basically, emissive texture is not supported by UE4 for lighting. To make it happen in D5 Render, the team applied SimpleGI and GI cache which lies the foundation to create high-quality emissive materials.
When the Emissive button is switched on, the material will instantly have a glowing effect. Designers can adjust its intensity, color as they need and decide whether it casts shadow or not.
Computer Graphics will never stop its pace to move forward. It's the same with D5 Render. As UE5 was released this year, the D5 Team is also making preparations for upgrade to bring a better rendering tool for 3D designers.