3D models (.obj or .fbx or .glb) do not load in Hololens 2 3d-viewer

Question

I am exporting simple 3D models as .obj, .fbx or .glb using blender, and succesfully display them in the 3D viewer app of a hololens 2. As soon as the models are more complex (for example created by makehuman), the exports cannot be displayed in Hololens 2 3d viewer app.The error message says that the models are not optimised for windows mixed reality. I found some documentation on the limitation of Hololens 1 .glb files. But I cannot find the specification for hololens 2 and the three file formats.

In addition: Should I reduced the complexity in the blender models, or during the export, or are there even tools to post-process 3D models for Hololens 2 / Windwos mixed reality?

Answer 1

You can use the following link as a guide for optimizing your models - Optimize your 3D models

Answer 2

The asset requirements for pre-installed 3D Viewer app on HoloLens 2, please see Asset requirements overview for more details, here is a quote to the main points::

1. Exporting - Assets must be delivered in the .glb file format (binary glTF)
2. Modeling - Assets must be less than 10k triangles, have no more than 64 nodes and 32 submeshes per LOD
3. Materials - Textures can't be larger than 4096 x 4096 and the smallest mip map should be no larger than 4 on either dimension
4. Animation - Animations can't be longer than 20 minutes at 30 FPS (36,000 keyframes) and must contain <= 8192 morph target vertices Optimizing - Assets should be optimized using the WindowsMRAssetConverter. Required on Windows OS Versions <= 1709* and recommended on Windows OS versions >= 1803

For the question of other tools to post-process 3D models, you can easily optimize any glTF 2.0 model using the Windows Mixed Reality Asset Converter available on GitHub. This tool includes a command line tool that uses these steps in sequence in order to convert a glTF 2.0 core asset for use in the Windows Mixed Reality home.

Answer 3

From my experience, only the simplest models will successfully open in 3D viewer, whether using HoloLens1 or 2. A primary reason is that even a model that "looks simple" could very well be comprised of well more than 10,000 polygons. For instance, a simple model of a screw, modeled originally in a CAD application, could be 10,000 polygons. So imagine how many polygons the whole product model would be!