RealityKit & Reality Composer Pro Q&A

A few questions about the intended usage of LowLevelRenderer / LowLevelRenderContextStandalone for custom rendering (custom Metal materials, dynamic meshes, custom splat compositing): visionOS custom shaders in immersive space LowLevelRenderer is listed as available on visionOS 27. Does that include user-authored Metal surface shaders via makeSurfaceShader when rendering in an immersive space, or are custom fragment shaders restricted there the way CustomMaterial was? Any foveation / Compositor Services constraints we should know about? Composition with RealityView Is LowLevelRenderer (via LowLevelRenderContextStandalone) intended only for fully standalone/offscreen rendering where the caller composites the output, or can it inject draws into an existing RealityView's managed render pass? On visionOS specifically, what's the supported way to get its output onto the drawable alongside RealityKit-rendered content with correct depth interaction (mutual occlusion between custom draws and normal entities)? Custom surface shader ABI For makeSurfaceShader with a user-authored Metal function: what's the function signature contract? Specifically — which [[buffer(n)]] / [[texture(n)]] slots are reserved by the renderer vs. available to the caller, how do camera and per-instance uniforms arrive in the shader, and how do LowLevelArgumentTable bindings map to argument indices? A pointer to sample code or header documentation for the shader-authoring contract would be ideal. Hot reload / resource lifetime For an authoring tool that recompiles shaders frequently: can LowLevelRenderContextStandalone.Resources be rebuilt incrementally, and what's the cost of re-init via the synchronous init(resources:) path? Any guidance on reusing resources across context instances? Relationship to GaussianSplatComponent Is GaussianSplatComponent built on LowLevelRenderer internally? For 4D / animated splats and counts above the component's internal limit, is implementing custom splat rendering directly on LowLevelRenderer a path you'd recommend, or discourage? Thank you!

The new GaussianSplatComponent: what's the supported ingestion path — standard .ply splats, .spz, or a conversion step inside RCP? And can a splat coexist in a scene with mesh geometry and depth-sort/occlude correctly against it, or are splats a separate pass with no depth interaction with meshes?

Hello, In the past my apps using animations were unable to use multiple animations. Following online guides, I put together sequences of animations and then used timestamps to playback the animation I wanted. Is there any intention for realitykit to support better selection of animations within our entities? Its somewhat of a limiting factor in what I am willing to do within reality kit. Thanks for the improvements to realitykit

RCP 3 Script Graphs in 27.0 appear to be JavaScript-backed and hot-reloadable. SceneKit historically exposed its scene graph to JavaScript via JavaScriptCore, so Apple has bridged a 3D framework to JS before. Questions about the runtime surface: Is there a public runtime API to evaluate JavaScript against a RealityKit scene, or to drive Script Graph behavior programmatically at runtime — or is the JS layer private SPI used only by RCP-authored, baked graphs? If there's a runtime JS layer, what object model is exposed — which entity/component types are bridged, and is that surface documented or intended to become public? What's the hot-reload mechanism, and is it reachable outside RCP's Preview on Device? Can a script graph be constructed or parameterized at runtime from a string, or is authoring strictly RCP-side with baked output loaded as an asset? We ship JavaScript scripting via JavaScriptCore ourselves, so a public RealityKit-to-JS binding would be a natural way to extend it — trying to understand what's public vs. private and the intended direction.

I’m using Reality Composer Pro 3 for a visionOS project, and I have a question about the editability of Shader Graph and other node-based systems. In RCP, Shader Graphs and other node graphs can be created and edited visually in the editor. I would like to know whether these graphs also have a supported code-based or text-based editing workflow. Specifically: Is there a public, documented file format for Shader Graphs in Reality Composer Pro 3 that developers can edit directly outside the RCP GUI? Can Shader Graph nodes, connections, parameters, and materials be generated or modified through code, scripts, or text files in a supported way? Does the same apply to other node graphs in RCP, such as behavior graphs or animation-related node graphs? If these graphs are stored internally inside the Reality Composer Pro project package, is it safe or supported to edit those underlying files directly? If direct editing is not supported, is there any recommended workflow for version control, reuse, templating, or programmatic generation of similar Shader Graph setups across multiple assets? My reason for asking is that I’m trying to build a more scriptable asset pipeline. For models and scene structure, it is often practical to generate or modify content through code. However, for complex Shader Graphs or node graphs, manually rebuilding similar node setups in the GUI can become repetitive and difficult to maintain. I’m not asking about private or unsupported internal formats. I’d like to understand whether Apple currently provides, or recommends, any supported workflow for code-driven editing, generation, reuse, or version control of Shader Graphs and other node graphs in Reality Composer Pro 3. Any guidance would be appreciated.

I have a question about material authoring improvements in Reality Composer Pro 3, especially for transparent or refractive PBR materials. In Reality Composer Pro 2, I found it difficult to create convincing glass-like materials. For example, the available Shader Graph nodes seemed limited for this use case, and I could not find common controls or nodes that are often useful for glass and crystal materials, such as Fresnel-style effects or more direct refraction-related controls. I would like to understand whether Reality Composer Pro 3 has improved this area. Specifically: Does Reality Composer Pro 3 provide better support for realistic glass, crystal, acrylic, or transparent PBR materials? Are there new Shader Graph nodes or material controls that help with Fresnel-style edge reflections, angle-dependent transparency, or similar effects? Does Reality Composer Pro 3 support index of refraction / IOR controls for transparent or refractive materials? Is there any supported way to create real refraction or physically plausible transmission for glass-like materials in RCP 3? If true refraction or IOR control is not supported, what is the recommended approach for creating convincing glass, crystal, or polished transparent materials for visionOS apps? Are there any sample projects, documentation pages, or WWDC sessions that show the recommended material setup for glass-like surfaces in Reality Composer Pro 3? My goal is to create visually believable glass and crystal-style materials inside the standard visionOS / RealityKit rendering pipeline, preferably using supported RCP material tools rather than unsupported shader workarounds. Any guidance on the current capabilities and recommended workflow in Reality Composer Pro 3 would be appreciated.

If I open a regular 2D window or a volumetric window while the ImmersiveSpace is active, is there any supported way for that window or volume to receive lighting from the immersive scene? For example, if I have lights, environment lighting, or other lighting setup inside the ImmersiveSpace, can those lights affect the content of a 2D window or a volumetric window opened by the same app? Or are windows, volumes, and immersive spaces rendered with separate lighting contexts? I’d like to understand the recommended approach if I want UI panels or small 3D volumes opened during an immersive experience to visually match the lighting of the immersive environment.

Can the new cloth sim be driven on a skinned character mesh — a cape pinned to the shoulders following skeletal animation — and does it run at interactive rates on visionOS, or is it aimed at non-real-time/hero content? Can a sim be cached/baked for deterministic playback?

Is it possible to utilize exr light maps rendered externally, for example in Blender, in Reality Composer Pro 3? I am thinking there might be a light map node in the material graph editor, that uses the same mixing modes as internally generated light maps, allowing workflows where light maps are rendered externally.

I seek advice on converting 3-D TIFF volumes, typically (1k)^3 16-bit unsigned integer, into guided and unguided Apple Vision Pro displays. My background is Mathematica (Wolfram) and ImageJ/Fiji applied to datasets collected at facilities such as the Advanced Photon Source at Argonne Natl. Lab. By guided, I mean a student/teacher situation such as used by MassVirtual to train aircraft mechanics and the chemistry software Nanome. By unguided, I mean the shared VR environment used by Shapr3D. For medical data, my current workflow is DICOM->Wolfram->Blender->Freeform, all on a Mac, then iCloud transfer of Freeform from Mac to Vision Pro. It works, but seems there should be something better. Suggestions?

Am I correct to understand that visionOS 27 brings the Vision API to the headset? What are the privacy restrictions on its use?

We're building animated and streamed Gaussian splat playback into Scenery, our native Apple AR/spatial authoring platform, and have a few questions about the intended usage of GaussianSplatComponent / GaussianSplatResource. Dynamic / animated splats (4D) Is mutating the underlying LowLevelBuffer behind a BufferResource at runtime a supported pattern, or is the component intended for static captures? BufferResource's init is @MainActor and the resource's bufferResource property is let, which suggests static intent. For animated (4D) splats, do we need to wrap a new BufferResource each frame and reassign it, or will in-place writes to the existing buffer be picked up by the renderer? If re-wrapping is required, is there a recommended cadence, and does it trigger a full re-sort/re-upload internally? LOD streaming / swapping Related: for streaming splat LOD, is swapping the BufferResource (or its buffers) at runtime supported, and is there a cost model we should design around — e.g. does a swap re-sort and re-upload everything, or can partial updates be done? Splat-count limit The BufferResource initializer throws past an internal limit (we're seeing ~200k). Is this limit fixed, memory-derived, or per-device? Is it per-component or per-scene — i.e. can we tile a large capture across multiple GaussianSplatComponents to exceed it? Any guidance on the intended ceiling and whether it's expected to change? Large captures as immersive environments We'd like to use a large splat capture as an environment the user walks inside (camera within the splat volume), rather than an object viewed from outside. Is this an intended use case? We're seeing splats appear to fade/break up as the camera gets very close — is that near-plane behavior, an opacity falloff, or the projection breaking down at close range, and can it be controlled? Does ProjectionMode.tangential help for inside-the-volume viewing? Thank you and appreciate the great updates!

I'm trying to create a hexagonal triplanar material in Reality Composer Pro 3 using Shader Graph. Could you provide guidance, or an example node setup, for creating a seamless hex-tile texture using triplanar projection? My goal is to apply a hex pattern to 3D objects without visible seams or texture stretching. Are there any sample projects, Shader Graph examples, or recommended workflows for achieving this in Reality Composer Pro?

Dear Apple Developer Team, I would like to ask a few questions related to RoomPlan, Room API, USDZ export, and possible future spatial scanning workflows: Can the RoomPlan or Room API load an existing USDZ room model and compare it in real time with a new live scan of the same space? Is Apple considering extending RoomPlan beyond indoor rooms, for example to scan outdoor areas, house exteriors, terrain, and simple building volumes with rough dimensions? Will RoomPlan support multi-floor continuous scanning, custom object detection elements, and reliable export of the scanned result to USDZ for further CAD/BIM workflows? Is it possible to create a real-time comparator between a reference object in USDZ or STEP format and a physical object being scanned live, so that deviations in geometry or dimensions can be detected during scanning? Best regards, Ivo Saina

I'm trying to create a hexagonal triplanar material in Reality Composer Pro 3 using Shader Graph. Could you provide guidance, or an example node setup, for creating a seamless hex-tile texture using triplanar projection? My goal is to apply a hex pattern to 3D objects without visible seams or texture stretching. Are there any sample projects, Shader Graph examples, or recommended workflows for achieving this in Reality Composer Pro? Thanks

Good Morning! Following the RCP 3 lightmap workflow: I've added Lightmap components to my entities and hit Bake, but I get "Lightmap bake failed: no lightmappable entities found — enable Process for Lightmaps in an asset's Geometry Transform Settings." I can't locate that flag anywhere in the GUI, and my scene objects are prototype instances. Could you walk through the complete end-to-end setup for baking lighting: where the Process for Lightmaps flag actually lives (on the instance or the source asset?), whether lightmap UVs must be authored or are auto-generated, and how the Lightmap component relates to that eligibility flag?

For Vision Pro's tiled GPU, how does MeshInstancesComponent compare to manually merging meshes for draw-call reduction? Does it collapse draw calls similarly while still allowing per-instance transform and material variation? Deciding whether to re-architect a heavy interior scene around it instead of hand-merging in Maya.

RCP 3's Animation Graph covers state machines and blending of imported clips. As an animator, is there now any in-editor support for authoring or editing animation curves and keyframes directly — a graph editor or dope sheet — or must all keyframe animation still be authored in a DCC (Maya/Blender) and imported as clips?

RCP 3 adds a lot of artist-facing surface: lightmaps, Animation Graph, Script Graph. Are step-by-step, artist-oriented tutorials planned beyond the API reference docs? A guided onboarding path would help 3D artists adopt these features much faster.

I’m familiar with using ModelSortGroupComponent to control draw order, but how does RealityKit determine the draw order between model sort groups? How can I enforce a specific draw order between two model sort groups that require different depth pass modes and therefore can't be combined into a single model sort group? Are there model bounding box tricks I can safely rely on?