Skip adding the LOD's renderer to the checked renderer if it's null

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -162,6 +162,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed null reference exception in Raytracing SSS volume component.
 - Fixed artifact appearing when diffuse and specular normal differ too much for eye shader with area lights
 - Fixed LightCluster debug view for ray tracing.
+- Fixed issue with RAS build fail when LOD was missing a renderer
 
 ### Changed
 - Changed Window/Render Pipeline/HD Render Pipeline Wizard to Window/Rendering/HDRP Wizard

com.unity.render-pipelines.high-definition/Editor/RenderPipeline/HDRenderPipelineMenuItems.cs

@@ -476,6 +476,7 @@ static void CheckSceneContentForRayTracing(MenuCommand menuCommand)
             // Flag that holds
             bool generalErrorFlag = false;
             var rendererArray = UnityEngine.GameObject.FindObjectsOfType<Renderer>();
+            var lodGroupArray = UnityEngine.GameObject.FindObjectsOfType<LODGroup>();
             List<Material> materialArray = new List<Material>(32);
             ReflectionProbe reflectionProbe = new ReflectionProbe();
 
@@ -573,10 +574,31 @@ static void CheckSceneContentForRayTracing(MenuCommand menuCommand)
 
                 if (!singleSided && hasSingleSided)
                 {
-                    Debug.LogWarning("The object " + currentRenderer.name + " has both double sided and single sided sub-meshes. The double sided flag will be ignored.");
+                    Debug.LogWarning("The object " + currentRenderer.name + " has both double sided and single sided sub-meshes. All materials will be considered double-sided for ray-traced effects.");
                     generalErrorFlag = true;
                 }
             }
+
+			//Check if one LOD is missing a renderer
+			for (var i = 0; i < lodGroupArray.Length; i++)
+            {
+                // Grab the current LOD group
+                LODGroup lodGroup = lodGroupArray[i];
+				LOD[] lodArray = lodGroup.GetLODs();
+                for (int lodIdx = 0; lodIdx < lodArray.Length; ++lodIdx)
+                {
+
+                    LOD currentLOD = lodArray[lodIdx];
+                    for (int rendererIdx = 0; rendererIdx < currentLOD.renderers.Length; ++rendererIdx)
+                    {
+                        if(currentLOD.renderers[rendererIdx] == null)
+						{
+							Debug.LogWarning("The LOD Group " + lodGroup.gameObject.name + " has at least one missing renderer in its children.");
+							generalErrorFlag = true;
+						}
+                    }
+                }
+			}
 
             if (!generalErrorFlag)
             {

com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/Raytracing/HDRaytracingManager.cs

@@ -492,6 +492,8 @@ internal void BuildRayTracingAccelerationStructure(HDCamera hdCamera)
                     for (int rendererIdx = 0; rendererIdx < currentLOD.renderers.Length; ++rendererIdx)
                     {
                         Renderer currentRenderer = currentLOD.renderers[rendererIdx];
+                        if(currentRenderer == null) continue;
+
                         // Add this fella to the renderer list
                         // Unfortunately, we need to check that this renderer was not already pushed into the list (happens if the user uses the same mesh renderer
                         // for two LODs)