diff --git a/src/medium/heterogeneous-flake.cpp b/src/medium/heterogeneous-flake.cpp
index 61b55ccf..c0075b0d 100644
--- a/src/medium/heterogeneous-flake.cpp
+++ b/src/medium/heterogeneous-flake.cpp
@@ -395,7 +395,9 @@ public:
 	}
 	
 	Float integrateDensities(Ray ray, Float length) const {
-		int nParts = std::max(1, (int) std::ceil(length/m_stepSize));
+		if (length == 0)
+			return 0.0f;
+		int nParts = (int) std::ceil(length/m_stepSize);
 		nParts += nParts % 2;
 		const Float stepSize = length/nParts;
 		const Vector increment = ray.d * stepSize;
@@ -421,8 +423,10 @@ public:
 		Float &currentSigmaT, 
 		Spectrum &currentAlbedo, 
 		Float desiredTau) const {
+		if (maxDist == 0)
+			return std::numeric_limits<Float>::infinity();
 
-		int nParts = std::max(1, (int) std::ceil(maxDist/m_stepSize));
+		int nParts = (int) std::ceil(maxDist/m_stepSize);
 		Float stepSize = maxDist/nParts;
 		Vector fullIncrement = ray.d * stepSize,
 			   halfIncrement = fullIncrement * .5f;
diff --git a/src/medium/heterogeneous-stencil.cpp b/src/medium/heterogeneous-stencil.cpp
index b279e953..8fc7b9e7 100644
--- a/src/medium/heterogeneous-stencil.cpp
+++ b/src/medium/heterogeneous-stencil.cpp
@@ -199,7 +199,9 @@ public:
 	}
 	
 	Float integrateDensities(Ray ray, Float length) const {
-		int nParts = std::max(1, (int) std::ceil(length/m_stepSize));
+		if (length == 0)
+			return 0.0f;
+		int nParts = (int) std::ceil(length/m_stepSize);
 		nParts += nParts % 2;
 		const Float stepSize = length/nParts;
 		const Vector increment = ray.d * stepSize;
@@ -225,7 +227,10 @@ public:
 		Float &currentSigmaT, 
 		Spectrum &currentAlbedo, 
 		Float desiredTau) const {
-		int nParts = std::max(1, (int) std::ceil(maxDist/m_stepSize));
+		if (maxDist == 0)
+			return std::numeric_limits<Float>::infinity();
+
+		int nParts = (int) std::ceil(maxDist/m_stepSize);
 		Float stepSize = maxDist/nParts;
 		Vector fullIncrement = ray.d * stepSize,
 			   halfIncrement = fullIncrement * .5f;