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diff --git a/intern/cycles/kernel/svm/bsdf_westin.h b/intern/cycles/kernel/svm/bsdf_westin.h
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+/* 
+ * Adapted from Open Shading Language with this license: 
+ * 
+ * Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al. 
+ * All Rights Reserved. 
+ * 
+ * Modifications Copyright 2011, Blender Foundation. 
+ *  
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions are 
+ * met: 
+ * * Redistributions of source code must retain the above copyright 
+ *   notice, this list of conditions and the following disclaimer. 
+ * * Redistributions in binary form must reproduce the above copyright 
+ *   notice, this list of conditions and the following disclaimer in the 
+ *   documentation and/or other materials provided with the distribution. 
+ * * Neither the name of Sony Pictures Imageworks nor the names of its 
+ *   contributors may be used to endorse or promote products derived from 
+ *   this software without specific prior written permission. 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+*/
+
+#ifndef __BSDF_WESTIN_H__
+#define __BSDF_WESTIN_H__
+
+CCL_NAMESPACE_BEGIN
+
+/* WESTIN BACKSCATTER */
+
+typedef struct BsdfWestinBackscatterClosure {
+	//float3 m_N;
+	float m_invroughness;
+} BsdfWestinBackscatterClosure;
+
+__device void bsdf_westin_backscatter_setup(ShaderData *sd, ShaderClosure *sc, float roughness)
+{
+	roughness = clamp(roughness, 1e-5f, 1.0f);
+	float m_invroughness = 1.0f/roughness;
+
+	sc->type = CLOSURE_BSDF_WESTIN_BACKSCATTER_ID;
+	sd->flag |= SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_GLOSSY;
+	sc->data0 = m_invroughness;
+}
+
+__device void bsdf_westin_backscatter_blur(ShaderClosure *sc, float roughness)
+{
+	float m_invroughness = sc->data0;
+	m_invroughness = min(1.0f/roughness, m_invroughness);
+	sc->data0 = m_invroughness;
+}
+
+__device float3 bsdf_westin_backscatter_eval_reflect(const ShaderData *sd, const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
+{
+	float m_invroughness = sc->data0;
+	float3 m_N = sd->N;
+
+	// pdf is implicitly 0 (no indirect sampling)
+	float cosNO = dot(m_N, I);
+	float cosNI = dot(m_N, omega_in);
+	if(cosNO > 0 && cosNI > 0) {
+		float cosine = dot(I, omega_in);
+		*pdf = cosine > 0 ? (m_invroughness + 1) * powf(cosine, m_invroughness) : 0;
+		*pdf *= 0.5f * M_1_PI_F;
+		return make_float3 (*pdf, *pdf, *pdf);
+	}
+	return make_float3 (0, 0, 0);
+}
+
+__device float3 bsdf_westin_backscatter_eval_transmit(const ShaderData *sd, const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
+{
+	return make_float3(0.0f, 0.0f, 0.0f);
+}
+
+__device float bsdf_westin_backscatter_albedo(const ShaderData *sd, const ShaderClosure *sc, const float3 I)
+{
+	return 1.0f;
+}
+
+__device int bsdf_westin_backscatter_sample(const ShaderData *sd, const ShaderClosure *sc, float randu, float randv, float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf)
+{
+	float m_invroughness = sc->data0;
+	float3 m_N = sd->N;
+
+	float cosNO = dot(m_N, sd->I);
+	if(cosNO > 0) {
+#ifdef __RAY_DIFFERENTIALS__
+		*domega_in_dx = sd->dI.dx;
+		*domega_in_dy = sd->dI.dy;
+#endif
+		float3 T, B;
+		make_orthonormals (sd->I, &T, &B);
+		float phi = 2 * M_PI_F * randu;
+		float cosTheta = powf(randv, 1 / (m_invroughness + 1));
+		float sinTheta2 = 1 - cosTheta * cosTheta;
+		float sinTheta = sinTheta2 > 0 ? sqrtf(sinTheta2) : 0;
+		*omega_in = (cosf(phi) * sinTheta) * T +
+				   (sinf(phi) * sinTheta) * B +
+				   (cosTheta) * sd->I;
+		if(dot(sd->Ng, *omega_in) > 0)
+		{
+			// common terms for pdf and eval
+			float cosNI = dot(m_N, *omega_in);
+			// make sure the direction we chose is still in the right hemisphere
+			if(cosNI > 0)
+			{
+				*pdf = 0.5f * M_1_PI_F * powf(cosTheta, m_invroughness);
+				*pdf = (m_invroughness + 1) * (*pdf);
+				*eval = make_float3(*pdf, *pdf, *pdf);
+#ifdef __RAY_DIFFERENTIALS__
+				// Since there is some blur to this reflection, make the
+				// derivatives a bit bigger. In theory this varies with the
+				// exponent but the exact relationship is complex and
+				// requires more ops than are practical.
+				*domega_in_dx *= 10.0f;
+				*domega_in_dy *= 10.0f;
+#endif
+			}
+		}
+	}
+	return LABEL_REFLECT|LABEL_GLOSSY;
+}
+
+/* WESTIN SHEEN */
+
+typedef struct BsdfWestinSheenClosure {
+	//float3 m_N;
+	float m_edginess;
+} BsdfWestinSheenClosure;
+
+__device void bsdf_westin_sheen_setup(ShaderData *sd, ShaderClosure *sc, float edginess)
+{
+	sc->type = CLOSURE_BSDF_WESTIN_SHEEN_ID;
+	sd->flag |= SD_BSDF|SD_BSDF_HAS_EVAL|SD_BSDF_GLOSSY;
+	sc->data0 = edginess;
+}
+
+__device void bsdf_westin_sheen_blur(ShaderClosure *sc, float roughness)
+{
+}
+
+__device float3 bsdf_westin_sheen_eval_reflect(const ShaderData *sd, const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
+{
+	float m_edginess = sc->data0;
+	float3 m_N = sd->N;
+
+	// pdf is implicitly 0 (no indirect sampling)
+	float cosNO = dot(m_N, I);
+	float cosNI = dot(m_N, omega_in);
+	if(cosNO > 0 && cosNI > 0) {
+		float sinNO2 = 1 - cosNO * cosNO;
+		*pdf = cosNI * M_1_PI_F;
+		float westin = sinNO2 > 0 ? powf(sinNO2, 0.5f * m_edginess) * (*pdf) : 0;
+		return make_float3 (westin, westin, westin);
+	}
+	return make_float3 (0, 0, 0);
+}
+
+__device float3 bsdf_westin_sheen_eval_transmit(const ShaderData *sd, const ShaderClosure *sc, const float3 I, const float3 omega_in, float *pdf)
+{
+	return make_float3(0.0f, 0.0f, 0.0f);
+}
+
+__device float bsdf_westin_sheen_albedo(const ShaderData *sd, const ShaderClosure *sc, const float3 I)
+{
+	return 1.0f;
+}
+
+__device int bsdf_westin_sheen_sample(const ShaderData *sd, const ShaderClosure *sc, float randu, float randv, float3 *eval, float3 *omega_in, float3 *domega_in_dx, float3 *domega_in_dy, float *pdf)
+{
+	float m_edginess = sc->data0;
+	float3 m_N = sd->N;
+
+	// we are viewing the surface from the right side - send a ray out with cosine
+	// distribution over the hemisphere
+	sample_cos_hemisphere(m_N, randu, randv, omega_in, pdf);
+	if(dot(sd->Ng, *omega_in) > 0) {
+		// TODO: account for sheen when sampling
+		float cosNO = dot(m_N, sd->I);
+		float sinNO2 = 1 - cosNO * cosNO;
+		float westin = sinNO2 > 0 ? powf(sinNO2, 0.5f * m_edginess) * (*pdf) : 0;
+		*eval = make_float3(westin, westin, westin);
+#ifdef __RAY_DIFFERENTIALS__
+		// TODO: find a better approximation for the diffuse bounce
+		*domega_in_dx = (2 * dot(m_N, sd->dI.dx)) * m_N - sd->dI.dx;
+		*domega_in_dy = (2 * dot(m_N, sd->dI.dy)) * m_N - sd->dI.dy;
+		*domega_in_dx *= 125.0f;
+		*domega_in_dy *= 125.0f;
+#endif
+	} else
+		pdf = 0;
+	return LABEL_REFLECT|LABEL_DIFFUSE;
+}
+
+CCL_NAMESPACE_END
+
+#endif /* __BSDF_WESTIN_H__ */
+