Using Unity 6 and PiXYZ Plugin 3.0.6, I get the following error when running PiXYZ Retopologize function with any models that have HDRP Lit Materials:
Exception: Albedo and opacity textures are null
UnityEditor.Pixyz.UnitySDK.Conversions.CombineAlbedoAndOpacity (UnityEngine.Pixyz.API.PiXYZAPI api, UnityEngine.Pixyz.Material.ColorOrTexture& albedo, UnityEngine.Pixyz.Material.CoeffOrTexture opacity, System.Collections.Generic.Dictionary2[TKey,TValue] map) (at ./Library/PackageCache/com.unity.pixyz.unity-sdk/Editor/Conversions/Modules/Material.cs:1221) UnityEditor.Pixyz.UnitySDK.Conversions.ToUnity (UnityEngine.Pixyz.Material.MaterialDefinition definition, UnityEngine.Pixyz.API.PiXYZAPI api, UnityEngine.Material material, System.Collections.Generic.Dictionary
2[TKey,TValue] map) (at ./Library/PackageCache/com.unity.pixyz.unity-sdk/Editor/Conversions/Modules/Material.cs:525)
UnityEditor.Pixyz.UnitySDK.Conversions.ToUnity (UnityEngine.Pixyz.Material.MaterialDefinition definition, UnityEngine.Pixyz.API.PiXYZAPI api, System.Collections.Generic.Dictionary2[TKey,TValue] map, UnityEngine.Shader shader, System.Boolean specularWorkflow, UnityEngine.Pixyz.Material.MaterialPatternType pattern) (at ./Library/PackageCache/com.unity.pixyz.unity-sdk/Editor/Conversions/Modules/Material.cs:495) UnityEditor.Pixyz.UnitySDK.SceneConverter.GetMaterials (UnityEditor.Pixyz.UnitySDK.SceneConverter+MaterialSyncType materialSync) (at ./Library/PackageCache/com.unity.pixyz.unity-sdk/Editor/Conversions/SceneConverter/SceneConverter.cs:1218) UnityEditor.Pixyz.UnitySDK.SceneConverter.ToUnity (System.UInt32 root, UnityEditor.Pixyz.UnitySDK.SceneConverter+MeshSyncType meshSyncType, System.Collections.Generic.Dictionary
2[TKey,TValue] entityToObject) (at ./Library/PackageCache/com.unity.pixyz.unity-sdk/Editor/Conversions/SceneConverter/SceneConverter.cs:1063)
UnityEditor.PixyzPlugin4Unity.Actions.PixyzAction.PostProcess (System.Collections.Generic.IList1[UnityEngine.GameObject]& output) (at ./Library/PackageCache/com.unity.industry.toolkit/Editor/Actions/PixyzAction.cs:197) System.Reflection.RuntimeMethodInfo.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at <321eb2db7c6d43ea8fc39b54eaca3452>:0) Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation. UnityEditor.PixyzPlugin4Unity.Actions.ActionBase.InvokePostProcess (System.Object& output) (at ./Library/PackageCache/com.unity.industry.toolkit/Editor/Actions/Actions.cs:563) UnityEditor.PixyzPlugin4Unity.Actions.ActionBase+<>c__DisplayClass85_0.<Execute>b__1 (System.Threading.Tasks.Task
1[TResult] task) (at ./Library/PackageCache/com.unity.industry.toolkit/Editor/Actions/Actions.cs:416)
UnityEngine.UnitySynchronizationContext:ExecuteTasks()