diff --git a/include/neural-graphics-primitives/testbed.h b/include/neural-graphics-primitives/testbed.h
index fc9b8992f..83e224207 100644
--- a/include/neural-graphics-primitives/testbed.h
+++ b/include/neural-graphics-primitives/testbed.h
@@ -877,8 +877,8 @@ class Testbed {
 		} training = {};
 
 		// tracing state
-		GPUMemory<vec3> pos[2] = {};
-		GPUMemory<VolPayload> payload[2] = {};
+		GPUMemory<vec3> pos[2] = {{}, {}};
+		GPUMemory<VolPayload> payload[2] = {{}, {}};
 		GPUMemory<uint32_t> hit_counter = {};
 		GPUMemory<vec4> radiance_and_density;
 	} m_volume;