#2463 でコンストラクターで Singleton 確保したのが仇に。

Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10NopSpringboneRuntime.cs

@@ -0,0 +1,44 @@
+using System.Threading.Tasks;
+using UniGLTF;
+using UniGLTF.SpringBoneJobs.Blittables;
+using UnityEngine;
+
+namespace UniVRM10
+{
+    /// <summary>
+    /// SpcriptedImporter 経由の import 向け。
+    /// NativeArray の確保や DontDestroyOnLoad を回避。
+    /// </summary>
+    public class Vrm10NopSpringboneRuntime : IVrm10SpringBoneRuntime
+    {
+        public void Dispose()
+        {
+        }
+
+        public Task InitializeAsync(Vrm10Instance instance, IAwaitCaller awaitCaller)
+        {
+            return Task.CompletedTask;
+        }
+
+        public void Process()
+        {
+        }
+
+        public bool ReconstructSpringBone()
+        {
+            return false;
+        }
+
+        public void RestoreInitialTransform()
+        {
+        }
+
+        public void SetJointLevel(Transform joint, BlittableJointMutable jointSettings)
+        {
+        }
+
+        public void SetModelLevel(Transform modelRoot, BlittableModelLevel modelSettings)
+        {
+        }
+    }
+}

Assets/VRM10/Runtime/Components/Vrm10Runtime/Vrm10NopSpringboneRuntime.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: b58249c702cd4054480f69562b43b0b7
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/VRM10/Runtime/IO/Vrm10Importer.cs

@@ -54,7 +54,24 @@ namespace UniVRM10
                 m_externalMap = new Dictionary<SubAssetKey, UnityEngine.Object>();
             }
 
-            m_springboneRuntime = springboneRuntime ?? new Vrm10FastSpringboneRuntime();
+            m_springboneRuntime = MakeDefaultRuntime(springboneRuntime, isAssetImport);
+        }
+
+        static IVrm10SpringBoneRuntime MakeDefaultRuntime(IVrm10SpringBoneRuntime runtime, bool isAssetImport)
+        {
+            if (runtime != null)
+            {
+                return runtime;
+            }
+
+            if (isAssetImport)
+            {
+                // 何もしない dummy
+                return new Vrm10NopSpringboneRuntime();
+            }
+
+            // Vrm10Instance.MakeRuntime に移譲
+            return null;
         }
 
         static void AssignHumanoid(List<VrmLib.Node> nodes, UniGLTF.Extensions.VRMC_vrm.HumanBone humanBone, VrmLib.HumanoidBones key)

ProjectSettings/QualitySettings.asset

@@ -230,6 +230,7 @@ QualitySettings:
     PSM: 5
     PSP2: 2
     Samsung TV: 2
+    Server: 0
     Standalone: 5
     Switch: 5
     Tizen: 2