Meta VR UI Setup

When to use this skill

Use this skill automatically when:

• Setting up a Canvas for VR
• Creating UI text with TextMesh Pro in a VR project
• Adding buttons, sliders, or other interactive UI in VR
• User reports pink/magenta text, unclickable buttons, or UI sizing issues in VR
• Configuring VR interaction (ray or poke) on a Canvas

Driving the Editor

Build the UI against an open Editor with unity-cli rather than hand-editing scene YAML — the Editor applies changes to the actual active scene.

unity status --format json          # look for state "ready"
unity command run_script --file AgentScripts/BuildUI.cs --entry BuildUI.Run --format json

Canvas construction is multi-component work, so it belongs in a run_script .cs file (kept outside Assets/, path relative to the project root) rather than a chain of single commands. Add --dry_run true to compile-check a script before it mutates the scene — but read the verdict from data.result.success: a compile failure still returns outer success: true and exit code 0, with the errors in data.result.diagnostics. Connecting, --project-path, and Safe Mode recovery are in the unity-cli skill; MCP equivalents are in references/unity-mcp-fallback.md.

Single-property reads and writes are cheaper as direct commands than as a script:

unity command get_component_properties --target MenuUI --type Canvas --format json
unity command set_transform --target MenuUI --position "[0,1.5,2]" --format json
unity command find_gameobjects --name MenuUI --format json

Array parameters take a JSON array in one argument (--position "[0,1.5,2]"). Space- or comma-separated components are rejected with INVALID_COMMAND_ARGS. Note set_transform writes local position — see the unity-placement skill for parented canvases.

Prerequisite: TMP Essential Resources

Before creating ANY VR UI, verify TMP resources are imported:

unity command find_assets --name "LiberationSans SDF" --format json

A data.result.count of 0 means they are missing — use the tmp-resources skill before proceeding.

Step 1: Create World Space Canvas

// AgentScripts/BuildUI.cs
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;
using UnityEngine.UI;

public static class BuildUI
{
    public static string Run()
    {
        // Adapt the name to match your canvas (e.g., "MainMenu", "SettingsUI")
        var go = new GameObject("MenuUI");
        var canvas = go.AddComponent<Canvas>();
        canvas.renderMode = RenderMode.WorldSpace;

        go.AddComponent<GraphicRaycaster>();

        // Remove CanvasScaler — not appropriate for VR
        var scaler = go.GetComponent<CanvasScaler>();
        if (scaler != null)
            Object.DestroyImmediate(scaler);

        var rt = go.GetComponent<RectTransform>();
        rt.localScale = new Vector3(0.001f, 0.001f, 0.001f);
        rt.sizeDelta = new Vector2(1920f, 1080f);
        rt.position = new Vector3(0f, 1.5f, 2f);

        Undo.RegisterCreatedObjectUndo(go, "Create VR Canvas");
        EditorSceneManager.MarkSceneDirty(EditorSceneManager.GetActiveScene());
        return $"Created VR Canvas '{go.name}'. Scale: {rt.localScale}, Size: {rt.sizeDelta}, Position: {rt.position}";
    }
}

Persist it when the shape is right:

unity command save_scene --format json

Canvas rules

• Render Mode: Always World Space. Screen Space modes break stereo rendering.
• Scale: 0.001 on all axes (1 unit in canvas = 1mm in world).
• CanvasScaler: Remove it. Physical size is controlled by world scale, not screen adaptation.
• Distance: Place 1.5-3m from user. Never closer than 0.5m. Max 5m for readable text.
• Physical size formula: Canvas sizeDelta * scale = meters. Example: 1920 * 0.001 = 1.92m wide.

Step 2: Create child UI elements

All child elements (panels, buttons, text) must follow these rules:

• localScale: Always [1, 1, 1]. Never scale children to compensate for canvas scale.
• localPosition.z: Always 0. Children must sit on the canvas plane.
• Size control: Use RectTransform.sizeDelta and anchors, never scale.

// AgentScripts/BuildPanel.cs
using TMPro;
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;
using UnityEngine.UI;

public static class BuildPanel
{
    public static string Run()
    {
        // Replace "MenuUI" with the actual canvas name used in Step 1
        var canvas = GameObject.Find("MenuUI");
        if (canvas == null) return "ERROR: Canvas 'MenuUI' not found.";

        // Panel
        var panel = new GameObject("ButtonPanel");
        panel.transform.SetParent(canvas.transform, false);
        var panelRT = panel.AddComponent<RectTransform>();
        panelRT.localScale = Vector3.one;
        panelRT.sizeDelta = new Vector2(800f, 600f);
        var panelImg = panel.AddComponent<Image>();
        panelImg.color = new Color(0.1f, 0.1f, 0.1f, 0.95f);
        panelImg.raycastTarget = false;

        var layout = panel.AddComponent<VerticalLayoutGroup>();
        layout.spacing = 50f;
        layout.padding = new RectOffset(80, 80, 100, 100);
        layout.childAlignment = TextAnchor.MiddleCenter;

        // Button
        var btnGO = new GameObject("StartButton");
        btnGO.transform.SetParent(panel.transform, false);
        var btnRT = btnGO.AddComponent<RectTransform>();
        btnRT.localScale = Vector3.one;
        btnRT.sizeDelta = new Vector2(400f, 120f);
        var btnImg = btnGO.AddComponent<Image>();
        btnImg.color = new Color(0.2f, 0.6f, 1f, 1f);
        btnGO.AddComponent<Button>();

        // Button text
        var textGO = new GameObject("Text");
        textGO.transform.SetParent(btnGO.transform, false);
        var textRT = textGO.AddComponent<RectTransform>();
        textRT.localScale = Vector3.one;
        textRT.anchorMin = Vector2.zero;
        textRT.anchorMax = Vector2.one;
        textRT.sizeDelta = Vector2.zero;
        var tmp = textGO.AddComponent<TextMeshProUGUI>();
        tmp.text = "Start";
        tmp.fontSize = 48f;
        tmp.color = new Color(0.95f, 0.95f, 0.95f, 1f);
        tmp.alignment = TextAlignmentOptions.Center;
        tmp.raycastTarget = false;

        Undo.RegisterCreatedObjectUndo(panel, "Create VR Panel");
        EditorSceneManager.MarkSceneDirty(EditorSceneManager.GetActiveScene());
        return $"Created panel with button. Panel scale: {panelRT.localScale}, Button scale: {btnRT.localScale}";
    }
}

Step 3: Validate created UI

Spot-check the canvas itself with a direct command:

unity command get_component_properties --target MenuUI --type Canvas --format json
unity command get_scene_hierarchy --format json                # whole active scene, incl. children

get_scene_hierarchy --path takes an open scene path, not a GameObject — --path MenuUI fails with "Scene 'MenuUI' is not open." Omit it and read the MenuUI subtree out of the active scene.

Editor checks only go so far — deploy the build and pull metavr capture screenshot from the headset to see the UI the way users will.

To sweep every child and auto-fix, use a script:

// AgentScripts/ValidateUI.cs
using System.Text;
using UnityEngine;

public static class ValidateUI
{
    public static string Run()
    {
        // Replace "MenuUI" with the actual canvas name
        var canvas = GameObject.Find("MenuUI");
        if (canvas == null) return "ERROR: Canvas not found.";

        var crt = canvas.GetComponent<RectTransform>();
        var c = canvas.GetComponent<Canvas>();
        var sb = new StringBuilder();

        if (c.renderMode != RenderMode.WorldSpace)
            sb.AppendLine("FAIL: Canvas renderMode is not World Space.");

        if (Mathf.Abs(crt.localScale.x - 0.001f) > 0.0001f)
            sb.AppendLine($"FAIL: Canvas scale is {crt.localScale}, expected 0.001.");

        foreach (Transform child in canvas.GetComponentsInChildren<Transform>(true))
        {
            if (child == canvas.transform) continue;
            var rt = child.GetComponent<RectTransform>();
            if (rt == null) continue;

            if (rt.localScale != Vector3.one)
            {
                sb.AppendLine($"FIXED: '{child.name}' had localScale {rt.localScale}, expected (1,1,1).");
                rt.localScale = Vector3.one;
            }
            if (Mathf.Abs(rt.localPosition.z) > 0.01f)
            {
                sb.AppendLine($"FIXED: '{child.name}' had localPosition.z={rt.localPosition.z}, expected 0.");
                rt.localPosition = new Vector3(rt.localPosition.x, rt.localPosition.y, 0f);
            }
        }

        return sb.Length == 0 ? "Validation PASSED. All properties correct." : sb.ToString();
    }
}

Common issues this catches:

• Canvas scale stuck at 1,1,1 instead of 0.001
• Child elements auto-scaled to compensate for parent (e.g., 1000x)
• Child elements offset on Z axis (e.g., localPosition.z = -2500)

Step 4: Add VR interaction (interactive UI only)

Only add interaction when your Canvas has interactive elements (buttons, sliders, dropdowns, toggles, input fields). Skip this for display-only UI (HUD, score, labels).

Decision tree

Does your Canvas have buttons, dropdowns, sliders, toggles, or input fields?
  YES -> Add VR interaction. Without it, interactive elements won't work in VR.
  NO  -> Skip. Display-only UI doesn't need interaction overhead.

Wiring it — ISDK Quick Actions

The supported entry point is the ISDK Quick Actions API, called through run_script. See the hz-unity-meta-interaction-sdk skill for signatures and the behavior these calls bake in.

// AgentScripts/AddCanvasInteraction.cs
using Oculus.Interaction.Editor.QuickActions;   // Editor-only assembly
using UnityEngine;

public static class AddCanvasInteraction
{
    public static string Run()
    {
        var target = GameObject.Find("MenuUI");
        QuickActionsAPI.AddRayCanvasInteraction(target);    // or AddPokeCanvasInteraction
        return "ok";
    }
}

These calls take the canvas's GameObject, not a Canvas component — passing Canvas is a compile error (cannot convert from 'UnityEngine.Canvas' to 'UnityEngine.GameObject'). Verified signatures:

Ray adds RayInteractable, PointableCanvas, an ISDK_RayCanvasInteraction child, and a scene-level Pointable Canvas Module. Poke adds PokeInteractable, PointableCanvas, and close-range collision detection.

Pass fixPointableCanvasModule: false when the PointableCanvasModule comes from a prefab or an unloaded additive scene, or you get a second one in the open scene.

If a Unity MCP server with the Meta Unity extension is what you have instead, the equivalent tools are meta_add_canvas_interaction_ray / meta_add_canvas_interaction_poke — see references/unity-mcp-fallback.md.

Verify interaction was added

unity command get_component_properties --target MenuUI --type PointableCanvas --format json
unity command find_gameobjects --name "Pointable Canvas Module" --format json

get_component_properties needs --type whenever --target is a GameObject (without it the call fails: "'type' is required when 'target' is a GameObject."), and it addresses one component rather than listing them — so name the component you are asserting. Success means the component is there; a failure naming the type means it is not.

PointableCanvas on the canvas plus a Pointable Canvas Module in the scene is the bar. Note that PointableElement wiring is assigned in Awake(), so on a prefab asset it always reads null — check the serialized field instead:

unity command get_serialized_fields --target <interactable> --field _pointableElement --format json

If buttons work in Editor but not on Meta VR device

The scene needs an interaction rig at runtime:

using Oculus.Interaction.OVR.Editor.QuickActions;
OVRQuickActionsAPI.AddOVRInteractionRig();      // also adds an OVRCameraRig if the scene has none

This provides all hand/controller interactors. See hz-unity-meta-interaction-sdk for the rig it builds and the "interactable authored without a rig present" caveat.

VR UI sizing reference

All sizes assume canvas scale of 0.001 (1 unit = 1mm).

Element sizes (minimum)

Button spacing

Minimum 50 units (5cm) between interactive elements to prevent mis-clicks.

Font sizes (at 0.001 canvas scale)

Never use auto-sizing in VR. Never use legacy Text components — always TextMeshPro.

Colors

• Text: off-white (0.9, 0.9, 0.9) or dark gray (0.1, 0.1, 0.1). Avoid pure white/black.
• Backgrounds: dark (0.1, 0.1, 0.1, 0.95) or light (0.9, 0.9, 0.9, 0.95).
• Contrast ratio: minimum 4.5:1, prefer 7:1+.
• Prefer opaque backgrounds over transparent (cheaper to render).

Performance tips

• Disable raycastTarget on non-interactive elements (labels, backgrounds, decorative images).
• Split static and dynamic content onto separate canvases to minimize rebuilds.
• Canvas rebuild cost should be < 1-2ms to maintain 72/90Hz.
• Share one SDF font asset per font family across all text elements.
• Disable canvases or GameObjects when not visible.

Troubleshooting

Checklists

Interactive UI (buttons, sliders, etc.)

[ ] TMP Essential Resources imported
[ ] Canvas: renderMode = World Space
[ ] Canvas: localScale = [0.001, 0.001, 0.001]
[ ] Canvas: positioned 1.5-3m from user
[ ] All children: localScale = [1, 1, 1]
[ ] All children: localPosition.z = 0
[ ] Sizes via sizeDelta, not scale
[ ] AddRayCanvasInteraction called on Canvas
[ ] PointableCanvas component verified on Canvas
[ ] Pointable Canvas Module exists in scene
[ ] Interaction rig present (AddOVRInteractionRig)
[ ] Buttons >= 250x100 units
[ ] Button spacing >= 50 units
[ ] Text >= 48pt, raycastTarget = false on non-interactive text
[ ] Validation script run and passed
[ ] Scene saved (unity command save_scene)

Display-only UI (HUD, score, labels)

[ ] TMP Essential Resources imported
[ ] Canvas: renderMode = World Space
[ ] Canvas: localScale = [0.001, 0.001, 0.001]
[ ] All children: localScale = [1, 1, 1]
[ ] All children: localPosition.z = 0
[ ] Text >= 48pt
[ ] raycastTarget = false on all elements
[ ] NO interaction components needed
[ ] Scene saved (unity command save_scene)

Integration with other skills

• tmp-resources: Use first to import TMP Essential Resources before creating any UI.
• hz-unity-meta-interaction-sdk: Owns the Quick Actions APIs used in Step 4.
• unity-placement: Use for positioning canvases relative to other scene objects.
• unity-cli: Connecting to an Editor, --project-path, Safe Mode recovery.