Which format file for 3d model SceneKit/ARKit better to use

Question

I read several tutorials how to place 3d objects in SceneKit/ARKit applications and all of them uses .scn format files for the objects.

But I found there is no any issues if I use original .dae format and do not convert it to .scn format.

I don't really see any difference between .dae and .scn formats.

Actually result seems to me the same but can you explain what the difference between them and what I should use in what cases?

Thank you!

Answer 1

The difference between .dae and .scn formats is significant. Collada .dae (which stands for data asset exchange) is a cross-platform XML-based schema file format used for graphics and visual effects in 3D authoring apps, like Maya or Blender. SceneKit's .scn is Xcode's native file format, which works in iOS and macOS apps. Unfortunately, scene's space, speed and hierarchical structure aren’t the .dae and .scn formats’ strong side. So, the most robust and effective today 3D file format that you can use in SceneKit/ARKit and RealityKit is a USDZ format.

USD family?–?Universal Scene Description, developed by Pixar. It is a cross-platform Python-based schema file format has the ability to create a 3D scenes by composing many sources files together into successively larger aggregations.

SceneKit formats

SceneKit supports many popular 3D formats. Geometry kept in those formats is visible thru ARSCNView.

• Collada's Digital Asset Exchange .dae

• Pixar's Zipped Universal Scene Description .usdz

• Pixar's ASCII Universal Scene Description .usda

• Pixar's Binary Universal Scene Description .usd, .usdc

• Wavefront Object .obj along with its material description .mtl

• Alembic interchange file format .abc

• Polygon file format .ply

• Stereolithography file format .stl

• Apple proprietary SceneKit Scene format .scn

• To convert .fbx and .glTF files into .usdz use command line.

RealityKit formats

Since 2019, the RealityKit framework has been gaining popularity. It works with the following three file formats:

• Pixar's Zipped Universal Scene Description .usdz

• Apple Reality Composer multi-scene hierarchy .rcproject

• Apple proprietary format (has much faster uploading time) .reality

Read about Reality Composer formats .rcproject and .reality here.