Preparing Models for AR

Overview

Hololens and Fologram limitations means that you may have to adapt your geometry for use in this workflow.

A rough benchmark is 1 million polygons for an acceptable augmented reality experience at 45 frames a second, note that sensitivity to framerates, delay and lag may vary widely between different people.

You can read more about Fologram's own benchmark here:

HoloLens 2 Polygon Count and Frame RateFologram

You can find Fologram's article on this topic here: https://community.fologram.com/t/how-to-prepare-your-models-for-mixed-reality-and-avoid-common-mistakes/86

Here are some more in-depth approaches for this process.

Managing Polygon Count

Left: Original mesh model. Right: Reduced mesh model. Model Credit: NEWPALMRYA

Cleaning Topology (Photogrammetry etc.)

If your 3D model is generated from elsewhere and is not suitable for reduction, you may attempt to retopologise your model so that it is easier to work with. Most 3D software has the ability to retopologise but we recommend InstantMeshes for control:

https://github.com/wjakob/instant-meshes - Download the pre-compiled binaries. Blender example workflow: https://www.youtube.com/watch?v=dKo0rWXVAlc

Reducing Polygon Counts

In most 3D software, there are options to reduce mesh sizes.

• In Rhino, you may try [Reduce Mesh]

• In Blender, you may try the [Decimate] Modifier

Note that this method will require management of textures. Refer to the section below on fidelity and Texture Baking

Low-Poly Meshes

In some instances, you may have to completely remodel your geometry with extremely reduced detail: https://www.youtube.com/watch?v=y7PdiGXbrD0

If you have the high-poly model, you can then bake textures, refer to section below on fidelity and Texture Baking

Rendering Fidelity

Fologram is limited to basic material controls and lighting interactions.

Texture Baking

For higher quality material finishes, you can attempt to bake these lighting qualities into the texture itself. This is a common process for optimising 3D real-time content, please find more information here:

pageUV and Lightmaps

Lighting effects are part of the image texture, removing the need for the lighting to be calculated and presented in real-time.

This works for most non-reflective material qualities and is recommended for at least diffuse, ambient occlusion, and shadow qualities.

This can be done in most 3D software, examples of documentation below:

• 3dsmax: https://knowledge.autodesk.com/support/3ds-max/learn-explore/caas/CloudHelp/cloudhelp/2021/ENU/3DSMax-Rendering/files/GUID-B67A2495-89E4-464A-8913-35C957E950EB-htm.html

• Blender: https://docs.blender.org/manual/en/latest/render/cycles/baking.html

Blender example: https://www.youtube.com/watch?v=r0M363A8um4

Texture Sizes

Fologram will automatically reduce texture sizes that are too large, if you have a large texture covering a large piece of geometry, it is recommended that you split the model into several pieces and adjust the textures to suit.

Examples

Example of baked texture maps for diffuse, global illumination, ambient occlusion and shadows:

Overall composition

Corresponding site texture with shadows of the house and trees baked in.

Corresponding house texture with shadows, diffuse colour reflected from the grass around it and shadows.