Hologram files in RemoteSpark

RemoteSpark supports sharing and viewing of 3D models as holograms. Below is the information needed to upload and share hologram files using RemoteSpark.

Accepted 3D model format

glTF (GL Transmission Language) 2.0 is currently the only hologram file format that’s supported in RemoteSpark. glTF is a royalty-free common publishing format for 3D content that minimizes processing power needed for use of the content.

To see the glTF file structure, a list of creation tools, content repositories, converters and exporters, optimizers, viewers, and other information, visit https://www.khronos.org/gltf/ .

Conversion of 3D models

Currently RemoteSpark does not support 3D model conversion within the application.

All models to be used in RemoteSpark must be exported from model creation or conversion software as zipped glTF 2.0 files.

File size and performance

Depending on network speeds (remember that the entire file does have to upload to the cloud, then download to the HoloLens), files below 10MB should load and render well in RemoteSpark.

10MB is not a hard limit on file size, as files as larger than 50MB have rendered in RemoteSpark. Whether the file will render after it’s completed uploading to the RemoteSpark cloud and downloading to the HoloLens often depends on the polygon and textures within the model.

The lower the texture size and polygon count in the model, the faster the load time to the HoloLens will be when viewing the model.

Polygons

Recommended maximum poly count: 1,000,000

Maximum poly count for optimal performance: 200,000

Textures and materials

Currently the only textures that are supported are Albedo/Diffuse maps, which should not be larger than 1024 x 1024 and work best in JPG format. Anything larger than 1024 x 1024 or in PNG or other image formats may hinder performance in RemoteSpark.

New to RemoteSpark 1.9 is the addition of transparency. Transparencies can be edited through the material settings within the modeling software before exporting, but not through textures.

Animations

Holograms (in glTF or .kspark format) can now display animations. RemoteSpark supports node animations (transformation, rotation, scale), but not morph/skeletal animations at this time.

An animation sequence can be broken down into steps and played one step at a time or all at once in one sequence. This currently needs to be done within a modelling program before it is exported, as shown below, the animation is broken into three steps using the Babylon exporter for 3DS Max.

Animated models have a Play/Pause and Reset button on the command bar when they’re displayed in a RemoteSpark session on the HoloLens. If they have a Multi-Step animation, they will display a Play All button on the command bar.

Colour and light considerations

When designing or exporting 3D models for HoloLens, consider the unique nature of additive displays and how that impacts things like colour, light and materials when they are rendered on the device. For further information, see Microsoft’s article on the subject.

Thumbnail

If you wish to see a thumbnail preview of the hologram from your Gallery or within the call when you’ve shared a hologram using RemoteSpark Expert, you’ll need to have the preview image titled ‘thumbnail’ in JPG format within the zip file of the hologram.

Thumbnail within the zip file

Thumbnail preview from Gallery

Adding Holograms to RemoteSpark

When the zipped file is complete the hologram can be added to the Gallery by following the steps outlined in this article:

Or the file can be directly added to the call by following the steps outlined in this article: