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 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.

Arkio on Mobile hardware

Quest 2 or later use a mobile processor, Meta recommends not loading more than 250.000 triangles on these devices to keep the experience running at a comfortable framerate. Arkio's supports loading larger models you can load models of up to 10M triangles (10.000.000) we recommend doing some testing to guarantee a comfortable performance for your users. If you need to view large models on a Quest or other mobile device we recommend turning off your shadows in view settings as this will boost performance.

To prevent mobile devices from crashing we added a maximum number of triangles and file size that can be loaded to Arkio. If imports 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. We recommend keeping your total number of imported triangles in the scene under 1.000.000 triangles so all supported Arkio devices can load the models comfortably.

If you want to load large 3D files in VR we recommend using a powerful PC connected to a VR headset. (eg. your Oculus Quest 2 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 100 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).