diff --git a/src/bsdfs/irawan.cpp b/src/bsdfs/irawan.cpp
index 753cd7d9..de3a8aea 100644
--- a/src/bsdfs/irawan.cpp
+++ b/src/bsdfs/irawan.cpp
@@ -19,7 +19,6 @@
     along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
-
 #include <mitsuba/render/bsdf.h>
 #include <mitsuba/render/shape.h>
 #include <mitsuba/render/texture.h>
@@ -37,9 +36,9 @@ MTS_NAMESPACE_BEGIN
  * This plugin implements the Irawan & Marschner woven cloth BRDF model
  * It is a port of a previous Java implementation by Piti Irawan. 
  *
- * To use the model, you must provide a special weave pattern file, as well
- * as diffuse and specular texture maps. For an example of what these look
- * like, please see the included example scenes.
+ * To use the model, you must provide a special weave pattern file --
+ * for an example of what these look like, please see the included 
+ * example scenes.
  *
  * For reference, the model is described in detail in the PhD
  * thesis of Piti Irawan ("The Appearance of Woven Cloth",
@@ -74,26 +73,25 @@ public:
 		SAssert(m_pattern.pattern.size() == 
 				m_pattern.tileWidth * m_pattern.tileHeight);
 		for (size_t i=0; i<m_pattern.pattern.size(); ++i)
-			SAssert(m_pattern.pattern[i] <= m_pattern.yarns.size()); 
+			SAssert(m_pattern.pattern[i] > 0 &&
+					m_pattern.pattern[i] <= m_pattern.yarns.size()); 
 
 		/* U and V tile count */
 		m_repeatU = props.getFloat("repeatU");
 		m_repeatV = props.getFloat("repeatV");
 
-		/* Diffuse and specular multiplier */
-		m_kd = props.getFloat("kd");
-		m_ks = props.getFloat("ks");
+		/* Diffuse and specular multipliers */
+		m_kdMultiplier = props.getFloat("kdMultiplier");
+		m_ksMultiplier = props.getFloat("ksMultiplier");
 	}
 
 	IrawanClothBRDF(Stream *stream, InstanceManager *manager) 
 		: BSDF(stream, manager) {
-		m_diffuseReflectance = static_cast<Texture2D *>(manager->getInstance(stream));
-		m_specularReflectance = static_cast<Texture2D *>(manager->getInstance(stream));
 		m_pattern = WeavePattern(stream);
 		m_repeatU = stream->readFloat();
 		m_repeatV = stream->readFloat();
-		m_kd = stream->readFloat();
-		m_ks = stream->readFloat();
+		m_kdMultiplier = stream->readFloat();
+		m_ksMultiplier = stream->readFloat();
 		m_componentCount = 1;
 		m_type = new unsigned int[m_componentCount];
 		m_combinedType = m_type[0] = EGlossyReflection | EAnisotropicMaterial;
@@ -120,10 +118,6 @@ public:
 		int yarnID = m_pattern.pattern[lookup.x + lookup.y * m_pattern.tileWidth] - 1;
 
 		const Yarn &yarn = m_pattern.yarns.at(yarnID);
-
-		Spectrum diffuse = m_diffuseReflectance->getValue(uv);
-		Spectrum specular = m_specularReflectance->getValue(uv);
-
 		// store center of the yarn segment
 		Point2 center
 			(((int) xy.x / m_pattern.tileWidth) * m_pattern.tileWidth 
@@ -195,7 +189,7 @@ public:
 
 		// Compute specular contribution.
 		Spectrum result(0.0f);
-		if (m_ks > 0.0f) {
+		if (m_ksMultiplier > 0.0f) {
 			Float integrand;
 			if (psi != 0.0f)
 				integrand = evalStapleIntegrand(u, v, om_i, om_r, m_pattern.alpha, 
@@ -218,18 +212,27 @@ public:
 				intensityVariation = std::min(-std::log(xi), (Float) 10.0f);
 			}
 
-			result = specular * (intensityVariation * m_ks * integrand);
+			result = yarn.ks * (intensityVariation * m_ksMultiplier * integrand);
 			if (type == Yarn::EWarp)
 				result *= (m_pattern.warpArea + m_pattern.weftArea) / m_pattern.warpArea;
 			else
 				result *= (m_pattern.warpArea + m_pattern.weftArea) / m_pattern.weftArea;
 		}
 
-		return result + diffuse * m_kd;
+		return result + yarn.kd * m_kdMultiplier;
 	}
 
 	Spectrum getDiffuseReflectance(const Intersection &its) const {
-		return m_diffuseReflectance->getValue(its);
+		Point2 uv = Point2(its.uv.x * m_repeatU,
+			(1 - its.uv.y) * m_repeatV);
+		Point2 xy(uv.x * m_pattern.tileWidth, uv.y * m_pattern.tileHeight); 
+		Point2i lookup(
+			modulo((int) xy.x, m_pattern.tileWidth),
+			modulo((int) xy.y, m_pattern.tileHeight));
+		int yarnID = m_pattern.pattern[lookup.x + lookup.y * m_pattern.tileWidth] - 1;
+		const Yarn &yarn = m_pattern.yarns.at(yarnID);
+
+		return yarn.kd * m_kdMultiplier;
 	}
 
 	Float pdf(const BSDFQueryRecord &bRec) const {
@@ -259,35 +262,14 @@ public:
 		return f(bRec);
 	}
 
-	void addChild(const std::string &name, ConfigurableObject *child) {
-		if (child->getClass()->derivesFrom(MTS_CLASS(Texture2D))
-				&& name == "diffuseReflectance") {
-			m_diffuseReflectance = static_cast<Texture2D *>(child);
-		} else if (child->getClass()->derivesFrom(MTS_CLASS(Texture2D))
-				&& name == "specularReflectance") {
-			m_specularReflectance = static_cast<Texture2D *>(child);
-		} else {
-			BSDF::addChild(name, child);
-		}
-	}
-
-	void configure() {
-		if (m_diffuseReflectance == NULL ||
-			m_specularReflectance == NULL)
-			Log(EError, "Missing texture component (diffuse "
-				"+ specular map are required)");
-	}
-
 	void serialize(Stream *stream, InstanceManager *manager) const {
 		BSDF::serialize(stream, manager);
 
-		manager->serialize(stream, m_diffuseReflectance.get());
-		manager->serialize(stream, m_specularReflectance.get());
 		m_pattern.serialize(stream);
 		stream->writeFloat(m_repeatU);
 		stream->writeFloat(m_repeatV);
-		stream->writeFloat(m_kd);
-		stream->writeFloat(m_ks);
+		stream->writeFloat(m_kdMultiplier);
+		stream->writeFloat(m_ksMultiplier);
 	}
 
 	/** parameters:
@@ -537,20 +519,21 @@ public:
 	std::string toString() const {
 		std::ostringstream oss;
 		oss << "IrawanClothBRDF[" << endl
-			<< "  diffuseReflectance = " << indent(m_diffuseReflectance.toString()) << "," << endl
-			<< "  specularReflectance = " << indent(m_specularReflectance.toString()) << endl
-			<< "  weavePattern = " << indent(m_pattern.toString()) << endl
+			<< "  weavePattern = " << indent(m_pattern.toString()) << "," << endl
+			<< "  repeatU = " << m_repeatU << "," << endl
+			<< "  repeatV = " << m_repeatV << "," << endl
+			<< "  kdMultiplier = " << m_kdMultiplier << "," << endl
+			<< "  ksMultiplier = " << m_ksMultiplier << endl
 			<< "]";
 		return oss.str();
 	}
 
 	MTS_DECLARE_CLASS()
 private:
-	ref<Texture2D> m_diffuseReflectance;
-	ref<Texture2D> m_specularReflectance;
 	WeavePattern m_pattern;
 	Float m_repeatU, m_repeatV;
-	Float m_kd, m_ks;
+	Float m_kdMultiplier;
+	Float m_ksMultiplier;
 };
 
 MTS_IMPLEMENT_CLASS_S(IrawanClothBRDF, false, BSDF)
diff --git a/src/bsdfs/irawan.h b/src/bsdfs/irawan.h
index f0f0a782..7e40bc9e 100644
--- a/src/bsdfs/irawan.h
+++ b/src/bsdfs/irawan.h
@@ -27,7 +27,6 @@
 #include <boost/spirit/include/phoenix_bind.hpp>
 #include <boost/spirit/include/phoenix_operator.hpp>
 #include <boost/spirit/include/phoenix_stl.hpp>
-#include <boost/spirit/include/support_istream_iterator.hpp>
 #include <boost/spirit/home/phoenix/bind/bind_member_variable.hpp>
 #include <boost/spirit/home/phoenix/bind/bind_member_function.hpp>
 #include <boost/spirit/home/phoenix/statement/if.hpp>
@@ -276,14 +275,6 @@ template <typename Iterator> struct SkipGrammar : qi::grammar<Iterator> {
 	qi::rule<Iterator> start;
 };
 
-inline Spectrum lookupSpectrum(const std::map<std::string, Spectrum> &map, const std::vector<char> &_name) {
-	std::string name = std::string(&_name[0]);
-	std::map<std::string, Spectrum>::const_iterator it = map.find(name);
-	if (it == map.end())
-		SLog(EError, "Unable to find key \"%s\"", name.c_str());
-	return it->second;
-}
-
 template <typename Iterator> struct YarnGrammar : qi::grammar<Iterator, Yarn(), SkipGrammar<Iterator> > {
 	YarnGrammar(const Properties &props) 
 			: YarnGrammar::base_type(start), props(props) {
@@ -297,14 +288,15 @@ template <typename Iterator> struct YarnGrammar : qi::grammar<Iterator, Yarn(),
 		type = (qi::string("warp") | qi::string("weft"))
 			[ ph::if_else(_1 == "warp", _val = Yarn::EWarp, _val = Yarn::EWeft ) ];
 
-		qi::rule<Iterator, std::string()> id = qi::lexeme[ lit('$') >> +char_("a-zA-Z0-9") ];
+		identifier = qi::lexeme[ lit('$') >> (qi::alpha | char_('_')) 
+			>> *(qi::alnum | char_('_')) ];
 
 		spec = ((lit("{") >> float_ >> lit(",") >> float_ >> lit(",") >> float_ >> lit("}")) 
 					[ ph::bind(&Spectrum::fromLinearRGB, _val, _1, _2, _3) ])
-		      | (id [ _val = bind(&Properties::getSpectrum, ph::ref(props), _1)]);
+		     | (identifier [ _val = bind(&Properties::getSpectrum, ph::ref(props), _1)]);
 
 		flt = (float_ [ _val = _1 ])
-		      | (id [ _val = bind(&Properties::getFloat, ph::ref(props), _1)]);
+		    | (identifier [ _val = bind(&Properties::getFloat, ph::ref(props), _1)]);
 
 		start = lit("yarn")
 			>> lit("{")
@@ -327,6 +319,7 @@ template <typename Iterator> struct YarnGrammar : qi::grammar<Iterator, Yarn(),
 	qi::rule<Iterator, Yarn(), SkipGrammar<Iterator> > start;
 	qi::rule<Iterator, Spectrum(), SkipGrammar<Iterator> > spec;
 	qi::rule<Iterator, float(), SkipGrammar<Iterator> > flt;
+	qi::rule<Iterator, std::string()> identifier;
 	const Properties &props;
 };
 
@@ -346,12 +339,13 @@ template <typename Iterator> struct WeavePatternGrammar : qi::grammar<Iterator,
 				>> uint_ [ push_back(_val, _1) ] % ','
 				>> lit("}");
 		
-		name = ("\"" >> *(char_ - "\"") >> "\"");
+		name = qi::lexeme [ lit("\"") >> *(char_ - "\"") >> lit("\"") ];
 
-		qi::rule<Iterator, std::string()> id = qi::lexeme[ lit('$') >> +char_("a-zA-Z0-9") ];
+		identifier = qi::lexeme[ lit('$') >> (qi::alpha | char_('_')) 
+			>> *(qi::alnum | char_('_')) ];
 
 		flt = (float_ [ _val = _1 ])
-		      | (id [ _val = bind(&Properties::getFloat, ph::ref(props), _1)]);
+		      | (identifier [ _val = bind(&Properties::getFloat, ph::ref(props), _1)]);
 
 		start = lit("weave") >> lit("{") >> (
 			  lit("name")               >> lit("=") >> name   [ bind(&WeavePattern::name,               _val) = _1 ]
@@ -372,13 +366,14 @@ template <typename Iterator> struct WeavePatternGrammar : qi::grammar<Iterator,
 			| pattern                                         [ bind(&WeavePattern::pattern,            _val) = _1 ] 
 			| yarn                                            [ push_back(bind(&WeavePattern::yarns, _val), _1)    ] 
 		) % ','
-		>> lit("}");
+		>> lit("}") >> qi::eoi;
 	}
 
 	qi::rule<Iterator, WeavePattern(), SkipGrammar<Iterator> > start;
 	qi::rule<Iterator, std::vector<uint32_t>(), SkipGrammar<Iterator> > pattern;
 	qi::rule<Iterator, std::string(), SkipGrammar<Iterator> > name;
 	qi::rule<Iterator, float(), SkipGrammar<Iterator> > flt;
+	qi::rule<Iterator, std::string()> identifier;
 	YarnGrammar<Iterator> yarn;
 	const Properties &props;
 };