Optimize larger 3D imports for Arkio on mobile devices

BIM/CAD models can be heavy and need some special attention before you can load their geometry into Arkio on smartphones and mobile VR devices. Here are some steps to keep your models clean so they can be loaded without problems by anyone in your meetings.

Quest and mobile hardware

Quest and Quest 2 use a mobile processor, Meta recommends not loading more than 250.000 polygons on a Quest to keep the experience running at a comfortable 72 fps. We ran tests with imported models up to 900.000 polygons but we don't recommend loading this many polygons as the experience can be uncomfortable. If you need to view large models on a Quest we recommend turning off your shadows in settings as this will boost performance considerably.

To prevent mobile devices from crashing we added a maximum number of polygons and file size. If models exceed these numbers the models will only be partially loaded, when the maximum file size is exceeded the models will not be loaded as your device will not have enough memory to process this file. We recommend keeping your total number of imported triangles in the scene under 450.000 polygons so all supported Arkio devices can load the models in a comfortable experience.

If you want to load larger 3D files in VR we recommend using a powerful PC connected to a VR headset. (eg. your Oculus Quest in air link mode) The maximum number of polygons supported by PC hardware is much higher and depending on your CPU, GPU, and Memory Arkio can import up to >10 Million polygon models. You can check your polygon count during the Revit export or when opening the OBJ file with the Windows 3D viewer.

If your model has too many polygons you can reduce the polygons using 3D mesh editing software like Blender, 3D Studio Max or model simplification tools like Simplygon

Revit model preparation - best practices

• Use a 3D section Box to crop only a part of your scene (fastest)
• For exporting, turn off (sub)categories, worksets and geometry you don't need (you don’t need to export furniture if you will only work on the exterior)
• The following (usual suspect) Revit categories can be hidden: Railings, Planting, Lighting Fixtures, Plumbing Fixtures, Electrical Equipment, Mechanical, Electrical and Piping Categories.
• Make use of Revit’s built-in detail visibility settings (Course, Medium, Detailed)  to reduce the detail of elements in Revit families
• Use Revit families without small corner fillets, and unneeded elements like 3D text, screws/bolts, keeping these objects don't only slow down Revit and your productivity but also your other tools
• Avoid loading CAD, Rhino and Sketchup references in your Revit model, they make Revit slow and take a longer time to export
• Avoid thin/overlapping surfaces and objects that might result in Z-fighting if plan to work on large scales, try to use minimum thicknesses of 100mm for solid objects
• Apply fewer materials to objects and simplify their count and usage. This will keep your Revit models cleaner and will make the conversion process faster. A useful workflow for this is making a multi-category material schedule organized by name and volume so you can easily spot unnecessary materials in your project:

Manual mesh optimization - step by step

1) Load your 3D file in 3D Studio using Link FBX (or use another 3D mesh modeling app like Blender)

3) Select Autodesk Revit Combine by material and bind the link after import (needed to see the number of polygons and optimize the model later on)

4) Delete all the non-mesh elements in the scene (camera, lights, and groups are not supported by OBJ)

5) Your Revit origin point might not make sense for placing/loading the object in Arkio, you can fix this for all meshes by right-clicking on the transform-tool and filling in a better position (or use the transform arrow with less accuracy)

6) click the [+] on your 3DS max viewport and configure the viewport to show the polygon statistics of your view

7) check the number of polygons of the meshes and use ProOptimize to the ones above 62.000 polygons. Try to keep the total number below 240.000 polygons to keep VR performance high.

8) Optimize a high poly mesh using ProOptimize tool. With the object selected Click on Modifier Tab > drop down list, search for “ProOptimizer”. Select the checkbox to keep the textures, click ‘Calculate’ > Reduce the ‘Vertex %’ to desired level and press ‘Enter. The polygon number of the selected object should be significantly reduced. You can check if the resulting geometry is acceptable in the scene.

9) Autodesk uses a different material system that other apps so the materials have to be converted to Standard Materials using a script or the built-in Scene converter. And the following settings:

10) Now we reached the final step of exporting the OBJ using the following settings. (Don’t forget to check the “flip YZ axis” checkbox as Autodesk uses a different coordinate system).