Revit graphics boost

The Revit graphics boost

Autodesk’s new One Graphics System (OGS) for Revit, 3ds max and other Autodesk applications will improve viewport performance and visual quality through GPU ray tracing

Autodesk is working on a new graphics engine that promises to ‘radically improve’ 3D performance in its core applications, including Revit, 3ds max and others.

The ‘next-generation’ system will also improve visual quality by delivering ray tracing directly inside the viewport. The aim is to enable users to switch between a simple shaded view and a photorealistic representation very quickly – though the speed at which this can happen will depend on the graphics hardware and the complexity of the model.

The new viewport system is a complete re-architecting of the current One Graphics System (OGS), which relies solely on rasterisation, a rendering method for 3D software that takes vector data and turns it into pixels (a raster image).

OGS is shared by nearly all Autodesk products, including Revit, 3ds max, AutoCAD, Inventor, Maya, Fusion, Infraworks, Navisworks and Recap. It dates back to 2007 and uses older graphics APIs including OpenGL and DirectX 9/10/11.

Revit, in particular, is notoriously poor at harnessing the plentiful power of modern Graphics Processing Units (GPUs). The graphics engine has only had small improvements over the years including the introduction of the ‘draw visible elements only’ feature in 2015. Co-developed by AMD, it was designed to improve viewport performance through ‘occlusion culling’, by not drawing elements in the current view that are obscured by others.

However, like many other CAD and BIM tools that use older graphics APIs, 3D performance in Revit has remained largely bottlenecked by the frequency of the CPU.

In fact, in AEC Magazine’s workstation tests we have seen as little as single digit percentage utilisation of GPU resources, which can result in poor 3D performance, especially when working with large models.

Autodesk’s ‘next generation’ viewport system should fix this, and users should get a much smoother viewport experience without having to rely on the software to simplify the model or turn off effects during view navigation.

By fully utilising modern graphics APIs including DirectX 12 and Vulkan, Autodesk’s applications will be able to talk straight to the GPU hardware (rather than having to route everything through the graphics driver) and take better advantage of multi-core CPUs.

The modernised OGS will also be able to use hardware-based ray tracing, which is built into modern graphics cards such as the new ‘Ampere’ Nvidia RTX, and forthcoming GPUs from AMD and Intel. It will utilise open standards, such as MaterialX and Pixar’s Hydra, part of USD.

Nvidia GTC showtime

gave a sneak peek of the ‘next-generation’ viewport system in a presentation at Nvidia’s GTC conference earlier this year.

Rather than looking at performance in simple shaded views, the focus was on the eye-catching stuff – real-time ray tracing.

The idea is that when working on a model in the viewport, an architect, engineer or designer can quickly switch to full ray traced quality at the click of a button. Revit currently relies on CPU rendering which takes a long time and the results can be mixed.

For the new engine, Vives explains that the emphasis is to provide a good real time experience, like you get with a game engine. “Photorealism is important, but we prioritise performance over quality,” he says.

According to Edstrom, it will be very easy to use for non-rendering experts. “They just need a very simple solution with literally no settings,” he says.

In Revit, for example, we imagine it will be just another visual style, to sit alongside the current wireframe, shaded, and realistic modes.

Lights, camera, action

hand how applications like Revit and GPUs in the future. In a demonstration of a path traced refer- Inventor are very CPU limited when it So when can we expect to see this new ence application, Vives showed a welding comes to 3D graphics and unable to take engine inside shipping Autodesk prodrobot model that originated in Autodesk advantage of the huge processing poten- ucts? In short, it’s too early to tell. In the Inventor. Render quality was photorealistic tial of modern GPUs. presentation it was described as a ‘very and looked impressive, much better than But, at Autodesk University 2019, when early work in progress’ and there were the rasterisation engine currently used in we asked what Autodesk was doing to no promises as to what will or will not be Autodesk Inventor 2022. improve 3D performance we got a rather supported in Autodesk’s products. But

The scene was lit by a single directional prickly response from CEO Andrew this is a standard line for a publicly tradlight and a low frequency environment Anagnost. There wasn’t an issue. ed company. The fact that Autodesk is light. Vives showed off the render quality While Autodesk would not publicly showing this in public now perhaps by highlighting several aspects within admit the current engine needed improv- shows promise for its 2023 or 2024 series the scene, including contact hardening ing, we expect work on the new OGS had of products. soft shadows, real ambient occlusion and already started back then. Swapping out Of course, a fast and eye-catching glossy reflections, focusing in on the sub- a graphics engine is a huge undertaking, viewport is not everything. In Revit, for tle reflection of a black socket on a red especially one that covers so many example, as highlighted by the Letters To paint finish. diverse applications as OGS does. Autodesk group in July 2020

In order to achieve a smooth viewport The fact is, there are many Autodesk (tinyurl.com/adesk-letter), there are many experience, the frame budget was set to 30 customers that struggle with large model other aspects of the BIM software that frames per second. This resulted in some performance, from load times to model need improving. Requests for large ‘noise’ when moving the camera, but the display and manipulation, relying on their model performance in general ranks high image resolved very quickly when idle by casting more rays and using denoising. ‘‘ Revit is notoriously poor at harnessing the on the Autodesk Revit roadmap (tinyurl.com/revitroadmap). While it’s good to see The presentation then went on to show the path tracing mode of the new plentiful power of modern GPUs. In fact, we have seen as little as single digit percentage Autodesk actively looking to improve the 3D graphics experience across the board, engine working inside in utilisation of GPU resources it’s long overdue and, with Autodesk 3ds Max, Maya and Inventor. You can watch the full presentation at tinyurl.com/ software to automatically simplify geome ’’ rise of powerful real-time engines like Unreal Engine in AEC, architects and designers now AutodeskOGS (registration required). try or turn off effects during view naviga- expect a fast and visually rich viewport tion in order to maintain frame rates. in CAD/BIM tools like Inventor and Flexible architecture Everyone wants more 3D performance, Revit. We’re excited to see how this develTo provide more flexibility for future and we expect many will be excited by ops, although that enthusiasm might not software and hardware developments, this news. Even more so, if they can get be shared by firms that have already the new viewport system is based on a this without having to upgrade GPU invested in real-time viz tools like decoupled architecture, where the appli- hardware. According to Vives, basically Enscape, Twinmotion and Lumion. cations and the graphic system are not as any GPU, up to five years old from any ■ tinyurl.com/AutodeskOGS intertwined as they are in the current vendor, will support the modernised OGS. OGS. This is being done through Hydra, The addition of real-time ray tracing in part of Pixar’s USD. the viewport is also a very exciting devel-

“That will allow us to make changes and opment. Rather than relying on slow improve OGS and add support for new CPU ray tracing, it will help bring visualfeatures and new APIs and new hardware isation more upfront in the design proand so on, without really involving the cess – not just for presentations but to application teams too much,” explains better understand complex forms Edstrom. “It also gives us the flexibility to through more realistic shading or to plug in other renderers, like Arnold, for explore materials and the impact of light. Autodesk’s new One Graphics System instance, that already supports the Hydra Those looking to take (OGS) will be able to take advantage render delegate API, or something like the advantage of real-time ray of new generation GPUs like the Nvidia Omniverse RTX renderer which tracing, however, will need Nvidia RTX A5000 which include hardware-based ray tracingalso supports this API… and there are to invest in a GPU with numerous others as well.” built in hardware ray

The system currently uses DirectX tracing. Currently, this Raytracing (DXR), but Autodesk is also would be an Nvidia planning to use the recently released RTX GPU but with Vulkan Ray tracing extensions. Autodesk taking an open approach Conclusion it will almost cerIn AEC Magazine’s workstation tests tainly extend to over the years we’ve experienced first- AMD and Intel