From 87f236cd10d8a0bc03fa775114d51e8a6a82d3fe Mon Sep 17 00:00:00 2001
From: Sergey Sharybin <sergey.vfx@gmail.com>
Date: Tue, 28 Feb 2017 17:33:06 +0100
Subject: [PATCH] Cycles: Fix division by zero in volume code which was
 producing -nan

---
 intern/cycles/kernel/kernel_volume.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/intern/cycles/kernel/kernel_volume.h b/intern/cycles/kernel/kernel_volume.h
index c7cb29b5af2..10d0d185345 100644
--- a/intern/cycles/kernel/kernel_volume.h
+++ b/intern/cycles/kernel/kernel_volume.h
@@ -966,7 +966,7 @@ ccl_device VolumeIntegrateResult kernel_volume_decoupled_scatter(
 			mis_weight = 2.0f*power_heuristic(pdf, distance_pdf);
 		}
 	}
-	if(sample_t < 1e-6f) {
+	if(sample_t < 1e-6f || pdf == 0.0f) {
 		return VOLUME_PATH_SCATTERED;
 	}