Sharing large 3D imports to any device

BIM/CAD models can have lots of details that need special attention if you plan to load all geometry on smartphones and mobile VR devices. Here are some tips for importing and working with large models in Arkio

Arkio's large-model tech

To allow the loading of large models on devices like the Meta Quest 3 Arkio dynamically adjusts the level of detail based on your viewpoint and device triangle budget. Things that are further away will render with fewer details and objects that are closer will show details that the device can still handle. 

Arkio automatically prepares and substitutes further away objects with simplified versions (called LODs). We also use occlusion culling to skip parts of the model that are obscured by other objects. This allows your device to load larger files than typically possible as only a small portion of a model's visible triangles is rendered. You can read more about this technology on our CTO's blog

Large models on mobile hardware

Devices like the Quest use a mobile processor. Arkio supports the loading of large models but not all your models triangles will be visible as we dynamically adjust the number of triangles shown to fit the device's render budget.

To prevent mobile devices with limited power and RAM from crashing there is a maximum direct import file size per device. When this maximum is exceeded this model can not be processed on that device. However, you can still process and place larger models on more powerful hardware like a PC/Mac first and then share these models with your less powerful devices using an Arkio meeting.

Loading extremely large files

A desktop PC/Mac has more memory and power to process large imported files to Arkio resources. Once your source files are processed in Arkio they can be placed in the scene and shared with less powerful devices using an Arkio meeting.

As an example, you might have a 35M triangle Revit building that you want to load on a Quest. Loading files this size via the Arkio cloud or using a USB cable will be too large for your Quest device to handle locally so it will fail and give you a warning. However, if you first import this Revit model in Arkio on a powerful PC/Mac and then place it in the Arkio scene you can share this large model with your Quest.

Large imports shared via Arkio meeting will only show the triangles that your devices can still handle. When loading extremely large files we recommend doing some tests to make sure your geometry looks and performs well on the device you are planing to use for a good collaborative experience.

We recommend keeping your total number of imported triangles in the scene under 5M triangles so all devices can load these models without issues. You can check your total triangles from our plugin exports, in the Arkio import panel or from the the View Settings in Arkio's review panel.

You can gain additional performance and see more details on a standalone headset by switching to VR instead of Mixed Reality and disabling your shadows, sections, or X-ray mode in view settings as this will boost performance by simplifying the rendering on your headset.

If you want to view extremely large models in VR we can also recommend switching to a PC in VR (air) link mode as your PC will be able to show more details and boost render quality vs a standalone headset.

Variable details per device

Based on your device's triangle render budgets (see above table) some details in your model can not load as there is simply too much geometry for that device to handle. In case you still want to see more details on that device you can consider the following options.

1) Reduce the imported model to only have the geometry you want to experience in higher detail and remove unnecessary parts that are unneeded. You can read more about optimizing your geometry here

2) Look at the same scene with more powerful hardware (eg. your Quest connected to a PC in air link mode) Your PC can render a higher number of triangles from the same viewpoint and also has improved rendering using ambient occlusion and better shadows and lighting see below comparison between Quest and PC VR from the same viewpoint.

828K/10.9M on Quest 3	5.4M/10.9M on Quest in PC link mode
636K/10.9M on Quest 3	5.9M/10.9M on Quest in PC link mode
747K/10.9M on Quest 3	5.0M/10.9M on Quest in PC link mode

Dynamic Occlusion

Arkio simplifies the geometry based on your view distance using a technique called dynamic occlusion which reduces details for parts of the model that are occluded by other geometry. This way details closer to the user can be maintained while objects that are obstructed and further away have reduced details.

When working with devices with low rendering budgets and dense triangle models this can result in artifacts for some viewpoints. Especially when your model has complex overlaps, long corridors, or geometry insets it can result in parts of the model looking less detailed and showing artifacts.

To prevent these low details from showing you can reduce dense triangle geometry from your exports so more render budget remains available for the most important details in your design. If you are experiencing these artifacts regularly we'd love to learn about your models and viewpoints so we can improve Arkio's HLOD system and Dynamic Occlusion for that type of geometry.