The geometry source When you call geometrySourcesForSemantic: you are given back an array of SCNGeometrySource objects with the given semantic in your case the sources for the vertex data). This data could have been encoded in many different ways and a multiple sources can use the same data with a different stride and offset. The … Read more
ARKit, RealityKit and SceneKit frameworks use 4 x 4 Transformation Matrices to translate, rotate, scale and shear 3D objects (just like simd_float4x4 matrix type). Let’s see how these matrices look like. In 3D Graphics we often use a 4×4 Matrix with 16 useful elements. The Identity 4×4 Matrix is as following: Between those sixteen elements … Read more
ARKit – Apply CIFilter to a specific vertices of ARFaceAnchor
Updated: October 08, 2022. TL;DR This post is not only about RealityKit, SceneKit & Metal, but also about related APIs and USD files. RealityKit 2.0 RealityKit (and RealityFoundation) is the youngest SDK in Apple family of rendering technologies. This high-level framework was released in 2019. RealityKit is made for AR / VR projects, has simplified … Read more
Typical depth buffers in a 3D graphics pipeline are not linear. Perspective division causes depths in normalized device coordinates to be on a different scale. (See also here.) So the z-coordinate you’re feeding into unprojectPoint isn’t actually the one you want. How, then, to find the normalized-depth coordinate matching a plane in world space? Well, … Read more
Updated: June 09, 2022. usdzconvert command in Xcode 14, 13, 12, 11 In macOS Ventura, Monterey, Big Sur and Catalina USDZ converter has a rich set of commands and supports more input formats for conversion than previous version. But before using it you need to download USDZ Tools. And don’t forget to setup a global … Read more
It might help to break down your issue into subproblems. Setting the Scene First, think about how to organize your scene to enable the kind of motion you want. You talk about moving the camera as if it’s attached to an invisible sphere. Use that idea! Instead of trying to work out the math to … Read more