diff --git a/src/ifcgeom/AbstractKernel.cpp b/src/ifcgeom/AbstractKernel.cpp
index a82e7c1641..a86a542895 100644
--- a/src/ifcgeom/AbstractKernel.cpp
+++ b/src/ifcgeom/AbstractKernel.cpp
@@ -3,6 +3,7 @@
 #include "../ifcgeom/IfcGeomElement.h"
 #include "../ifcgeom/ConversionSettings.h"
 #include "../ifcgeom/abstract_mapping.h"
+#include "../ifcgeom/piecewise_function_evaluator.h"
 
 #ifdef IFOPSH_WITH_OPENCASCADE
 #include "../ifcgeom/kernels/opencascade/OpenCascadeKernel.h"
@@ -220,7 +221,8 @@ bool ifcopenshell::geometry::kernels::AbstractKernel::convert_impl(const taxonom
 }
 
 bool ifcopenshell::geometry::kernels::AbstractKernel::convert_impl(const taxonomy::piecewise_function::ptr item, IfcGeom::ConversionResults& cs) {
-	auto expl = item->evaluate();
+   piecewise_function_evaluator evaluator(item);
+   auto expl = evaluator.evaluate();
 	expl->instance = item->instance;
 	return convert(expl, cs);
 }
diff --git a/src/ifcgeom/mapping/IfcCompositeCurve.cpp b/src/ifcgeom/mapping/IfcCompositeCurve.cpp
index b9f2aaaf4d..568b861ad7 100644
--- a/src/ifcgeom/mapping/IfcCompositeCurve.cpp
+++ b/src/ifcgeom/mapping/IfcCompositeCurve.cpp
@@ -92,7 +92,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcCompositeCurve* inst) {
 		return loop;
 	}
 	else {
-      auto pwf = taxonomy::make<taxonomy::piecewise_function>(0.0,pwfs,&settings_,inst);
+      auto pwf = taxonomy::make<taxonomy::piecewise_function>(0.0,pwfs,inst);
 		return pwf;
 	}
 }
diff --git a/src/ifcgeom/mapping/IfcCurveSegment.cpp b/src/ifcgeom/mapping/IfcCurveSegment.cpp
index 343cb8300d..e2f38135e3 100644
--- a/src/ifcgeom/mapping/IfcCurveSegment.cpp
+++ b/src/ifcgeom/mapping/IfcCurveSegment.cpp
@@ -961,7 +961,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcCurveSegment* inst) {
 
     taxonomy::piecewise_function::spans_t spans;
     spans.emplace_back(fabs(length), fn);
-    auto pwf = taxonomy::make<taxonomy::piecewise_function>(0.0, spans,&settings_,inst);
+    auto pwf = taxonomy::make<taxonomy::piecewise_function>(0.0, spans,inst);
     return pwf;
 }
 
diff --git a/src/ifcgeom/mapping/IfcFixedReferenceSweptAreaSolid.cpp b/src/ifcgeom/mapping/IfcFixedReferenceSweptAreaSolid.cpp
index 7267f61b2a..79632b9f01 100644
--- a/src/ifcgeom/mapping/IfcFixedReferenceSweptAreaSolid.cpp
+++ b/src/ifcgeom/mapping/IfcFixedReferenceSweptAreaSolid.cpp
@@ -18,6 +18,7 @@
  ********************************************************************************/
 
 #include "mapping.h"
+#include "../piecewise_function_evaluator.h"
 #define mapping POSTFIX_SCHEMA(mapping)
 using namespace ifcopenshell::geometry;
 
@@ -34,6 +35,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcFixedReferenceSweptAreaSolid
 
 	// @todo currently only the case is handled where directrix returns a piecewise_function
 	if (auto pwf = taxonomy::dcast<taxonomy::piecewise_function>(dir)) {
+      piecewise_function_evaluator evaluator(pwf,&settings_);
 		double start = 0;
 		double end = pwf->length();
 #ifdef SCHEMA_HAS_IfcDirectrixCurveSweptAreaSolid
@@ -53,20 +55,9 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcFixedReferenceSweptAreaSolid
 			}
 		}
 #endif
-		auto curve_length = end - start;
-		auto param_type = settings_.get<ifcopenshell::geometry::settings::PiecewiseStepType>().get();
-		auto param = settings_.get<ifcopenshell::geometry::settings::PiecewiseStepParam>().get();
-		size_t num_steps = 0;
-		if (param_type == ifcopenshell::geometry::settings::PiecewiseStepMethod::MAXSTEPSIZE) {
-			// parameter is max step size
-			num_steps = (size_t) std::ceil(curve_length / param);
-		} else {
-			// parameter is minimum number of steps
-			num_steps = (size_t) std::ceil(param);
-		}
-		for (size_t i = 0; i <= num_steps; ++i) {
-			auto distalong = start + curve_length / num_steps * i;
-			auto m4 = pwf->evaluate(distalong);
+      auto evaluation_points = evaluator.evaluation_points();
+      for (const auto& dist_along : evaluation_points) {
+          auto m4 = evaluator.evaluate(dist_along);
 			
 			/*
 			std::stringstream ss;
diff --git a/src/ifcgeom/mapping/IfcGradientCurve.cpp b/src/ifcgeom/mapping/IfcGradientCurve.cpp
index 3c5b95635a..6217b81a0e 100644
--- a/src/ifcgeom/mapping/IfcGradientCurve.cpp
+++ b/src/ifcgeom/mapping/IfcGradientCurve.cpp
@@ -18,6 +18,7 @@
  ********************************************************************************/
 
 #include "mapping.h"
+#include "../piecewise_function_evaluator.h"
 #define mapping POSTFIX_SCHEMA(mapping)
 using namespace ifcopenshell::geometry;
 
@@ -55,7 +56,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcGradientCurve* inst) {
    double gradient_start = m(0, 3); // start of vertical (row 0, col 3) - "Distance Along" horizontal curve
 
 	// create the vertical pwf
-	auto vertical = taxonomy::make<taxonomy::piecewise_function>(gradient_start, pwfs, &settings_);
+	auto vertical = taxonomy::make<taxonomy::piecewise_function>(gradient_start, pwfs);
 
 	// Determine the valid domain of the PWF... the valid domain is where both
 	// the base curve and gradient curves are defined
@@ -69,11 +70,12 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcGradientCurve* inst) {
    }
 
 	// define the callback function for the gradient curve
-	auto composition = [horizontal, vertical](double u)->Eigen::Matrix4d {
+   piecewise_function_evaluator horizontal_evaluator(horizontal, &settings_), vertical_evaluator(vertical, &settings_);
+   auto composition = [horizontal_evaluator, vertical_evaluator,start=vertical->start()](double u) -> Eigen::Matrix4d {
 		// u is distance from start of gradient curve (vertical)
 		// add vertical->start() to u to get distance from start of horizontal
-      auto xy = horizontal->evaluate(u + vertical->start());
-		auto uz = vertical->evaluate(u);
+      auto xy = horizontal_evaluator.evaluate(u + start);
+      auto uz = vertical_evaluator.evaluate(u);
 
       uz.col(3)(0) = 0.0; // x is distance along. zero it out so it doesn't add to the x from horizontal
       uz.col(1).swap(uz.col(2)); // uz is 2D in distance along - y plane, swap y and z so elevations become z
@@ -86,7 +88,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcGradientCurve* inst) {
 
 	taxonomy::piecewise_function::spans_t spans;
    spans.emplace_back(length, composition);
-   auto pwf = taxonomy::make<taxonomy::piecewise_function>(start, spans, &settings_, inst);
+   auto pwf = taxonomy::make<taxonomy::piecewise_function>(start, spans, inst);
    return pwf;
 }
 
diff --git a/src/ifcgeom/mapping/IfcOffsetCurveByDistance.cpp b/src/ifcgeom/mapping/IfcOffsetCurveByDistance.cpp
index 7af8b42bd8..1ed4d05e8b 100644
--- a/src/ifcgeom/mapping/IfcOffsetCurveByDistance.cpp
+++ b/src/ifcgeom/mapping/IfcOffsetCurveByDistance.cpp
@@ -19,6 +19,7 @@
 
 #include "mapping.h"
 #include "../profile_helper.h"
+#include "../piecewise_function_evaluator.h"
 #define mapping POSTFIX_SCHEMA(mapping)
 using namespace ifcopenshell::geometry;
 
@@ -144,11 +145,12 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcOffsetCurveByDistances* inst
          offset_spans.emplace_back(l, fn);
     }
 
-   auto offsets = taxonomy::make<taxonomy::piecewise_function>(start,offset_spans,&settings_);
+   auto offsets = taxonomy::make<taxonomy::piecewise_function>(start,offset_spans);
 
-	auto composition = [pw_curve, offsets](double u) -> Eigen::Matrix4d {
-      auto p = pw_curve->evaluate(u);
-		auto offset = offsets->evaluate(u);
+   piecewise_function_evaluator pw_evaluator(pw_curve, &settings_), offsets_evaluator(offsets, &settings_);
+   auto composition = [pw_evaluator, offsets_evaluator](double u) -> Eigen::Matrix4d {
+      auto p = pw_evaluator.evaluate(u);
+      auto offset = offsets_evaluator.evaluate(u);
       Eigen::Matrix4d m = p * offset;
       return m;
 	};
@@ -157,7 +159,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcOffsetCurveByDistances* inst
    // this may change depending on decisions in the bSI-IF
    taxonomy::piecewise_function::spans_t spans;
    spans.emplace_back(basis_curve_length, composition);
-	auto pwf = taxonomy::make<taxonomy::piecewise_function>(start,spans,&settings_,inst);
+	auto pwf = taxonomy::make<taxonomy::piecewise_function>(start,spans,inst);
 	return pwf;
 }
 
diff --git a/src/ifcgeom/mapping/IfcPointByDistanceExpression.cpp b/src/ifcgeom/mapping/IfcPointByDistanceExpression.cpp
index 601765e1a3..6097344eb3 100644
--- a/src/ifcgeom/mapping/IfcPointByDistanceExpression.cpp
+++ b/src/ifcgeom/mapping/IfcPointByDistanceExpression.cpp
@@ -19,6 +19,7 @@
 
 #include "mapping.h"
 #include "../profile_helper.h"
+#include "../piecewise_function_evaluator.h"
 
 #define mapping POSTFIX_SCHEMA(mapping)
 using namespace ifcopenshell::geometry;
@@ -31,7 +32,8 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcPointByDistanceExpression* i
    //auto item = map(basis_curve);
    //auto pw_curve = ifcopenshell::geometry::piecewise_from_item(item);
    auto pw_curve = taxonomy::dcast<taxonomy::piecewise_function>(map(inst->BasisCurve()));
-   auto m = pw_curve->evaluate(u);
+   piecewise_function_evaluator evaluator(pw_curve,&settings_);
+   auto m = evaluator.evaluate(u);
 
    auto o = m.col(3).head<3>();
    auto z = m.col(2).head<3>();
diff --git a/src/ifcgeom/mapping/IfcSectionedSolidHorizontal.cpp b/src/ifcgeom/mapping/IfcSectionedSolidHorizontal.cpp
index 74e6e4cd89..95b750f82f 100644
--- a/src/ifcgeom/mapping/IfcSectionedSolidHorizontal.cpp
+++ b/src/ifcgeom/mapping/IfcSectionedSolidHorizontal.cpp
@@ -22,6 +22,7 @@
 using namespace ifcopenshell::geometry;
 
 #include "../../ifcgeom/profile_helper.h"
+#include "../piecewise_function_evaluator.h"
 
 #include <boost/range/combine.hpp>
 
@@ -114,7 +115,8 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcSectionedSolidHorizontal* in
 	// @todo currently only the case is handled where directrix returns a piecewise_function
 	// @todo this "if" statement is not really required because the function returns at the start if the Directrix is not a piecewise function
 	if (pwf) {
-		double start = std::max(0., cross_sections.front().dist_along);
+      piecewise_function_evaluator evaluator(pwf, &settings_);
+      double start = std::max(0., cross_sections.front().dist_along);
 		double end = std::min(pwf->length(), cross_sections.back().dist_along);
 
 		if (end - start < 1.e-9) {
@@ -232,7 +234,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcSectionedSolidHorizontal* in
 				}
 			}
 
-			auto m4 = pwf->evaluate(dist_along);
+			auto m4 = evaluator.evaluate(dist_along);
 			/* {
 				std::wcout << "#" << pwf->instance->data().id() << " " << dist_along << ": " << m4.col(3).row(2).value() << std::endl;
 			}*/
diff --git a/src/ifcgeom/mapping/IfcSegmentedReferenceCurve.cpp b/src/ifcgeom/mapping/IfcSegmentedReferenceCurve.cpp
index 2ab56482c1..d1ab88fbe5 100644
--- a/src/ifcgeom/mapping/IfcSegmentedReferenceCurve.cpp
+++ b/src/ifcgeom/mapping/IfcSegmentedReferenceCurve.cpp
@@ -21,6 +21,8 @@
 #define mapping POSTFIX_SCHEMA(mapping)
 using namespace ifcopenshell::geometry;
 
+#include "../piecewise_function_evaluator.h"
+
 #ifdef SCHEMA_HAS_IfcSegmentedReferenceCurve
 
 taxonomy::ptr mapping::map_impl(const IfcSchema::IfcSegmentedReferenceCurve* inst) {
@@ -53,7 +55,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcSegmentedReferenceCurve* ins
     const Eigen::Matrix4d& m = p->ccomponents();
     double cant_start = m(0, 3); // start of cant curve
 
-   auto cant = taxonomy::make<taxonomy::piecewise_function>(cant_start,pwfs,&settings_);
+   auto cant = taxonomy::make<taxonomy::piecewise_function>(cant_start,pwfs);
 
     // Determine the valid domain of the PWF... the valid domain is where 
     // horizontal, gradient and cant curves are defined
@@ -68,11 +70,12 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcSegmentedReferenceCurve* ins
     }
 
     // define the callback function for the segmented reference curve
-	auto composition = [gradient, cant](double u)->Eigen::Matrix4d {
+    piecewise_function_evaluator gradient_evaluator(gradient, &settings_), cant_evaluator(cant, &settings_);
+    auto composition = [gradient_evaluator, cant_evaluator, start = cant->start()](double u) -> Eigen::Matrix4d {
       // u is distance from start of cant curve
       // add cant->start() to u to get the distance from start of gradient curve
-		auto g = gradient->evaluate(u+cant->start());
-		auto c = cant->evaluate(u);
+      auto g = gradient_evaluator.evaluate(u + start);
+      auto c = cant_evaluator.evaluate(u);
 
       // Need to multiply g and c so the axis vectors
       // from cant have the correct rotation applied so
@@ -105,7 +108,7 @@ taxonomy::ptr mapping::map_impl(const IfcSchema::IfcSegmentedReferenceCurve* ins
 
 	taxonomy::piecewise_function::spans_t spans;
    spans.emplace_back(length, composition);
-   auto pwf = taxonomy::make<taxonomy::piecewise_function>(start, spans, &settings_, inst);
+   auto pwf = taxonomy::make<taxonomy::piecewise_function>(start, spans, inst);
    return pwf;
 }
 
diff --git a/src/ifcgeom/piecewise_function_evaluator.cpp b/src/ifcgeom/piecewise_function_evaluator.cpp
new file mode 100644
index 0000000000..e4a03511ca
--- /dev/null
+++ b/src/ifcgeom/piecewise_function_evaluator.cpp
@@ -0,0 +1,103 @@
+#include "piecewise_function_evaluator.h"
+#include "profile_helper.h"
+
+using namespace ifcopenshell::geometry;
+
+
+piecewise_function_evaluator::piecewise_function_evaluator(taxonomy::piecewise_function::const_ptr pwf, ifcopenshell::geometry::Settings* settings) : pwf_(pwf) {
+    if (settings) {
+        settings_ = *settings;
+    }
+}
+
+std::vector<double> piecewise_function_evaluator::evaluation_points() const {
+    if (!eval_points_.has_value()) {
+        double curve_length = pwf_->length();
+
+        auto param_type = settings_.get<ifcopenshell::geometry::settings::PiecewiseStepType>().get();
+        auto param = settings_.get<ifcopenshell::geometry::settings::PiecewiseStepParam>().get();
+        unsigned num_steps = 0;
+        if (param_type == ifcopenshell::geometry::settings::PiecewiseStepMethod::MAXSTEPSIZE) {
+            // parameter is max step size
+            num_steps = (unsigned)std::ceil(curve_length / param);
+        } else {
+            // parameter is minimum number of steps
+            num_steps = (unsigned)std::ceil(param);
+        }
+
+        eval_points_ = evaluation_points(pwf_->start(), pwf_->start() + curve_length, num_steps);
+    }
+    return *eval_points_;
+}
+
+std::vector<double> piecewise_function_evaluator::evaluation_points(double ustart, double uend, unsigned nsteps) const {
+    double curve_length = pwf_->length();
+    ustart = std::max(pwf_->start(), ustart);
+    uend = std::min(uend, pwf_->start() + curve_length);
+
+    nsteps = std::max(1u, nsteps); // never have fewer than 1 step
+
+    auto resolution = (uend - ustart) / nsteps;
+
+    std::vector<double> u_values;
+    u_values.reserve(nsteps);
+
+    for (unsigned i = 0; i <= nsteps; ++i) {
+        auto u = resolution * i + ustart;
+        u_values.push_back(u);
+    }
+
+    return u_values;
+}
+
+taxonomy::item::ptr piecewise_function_evaluator::evaluate() const {
+    return evaluate(evaluation_points());
+}
+
+taxonomy::item::ptr piecewise_function_evaluator::evaluate(double ustart, double uend, unsigned nsteps) const {
+    return evaluate(evaluation_points(ustart, uend, nsteps));
+}
+
+Eigen::Matrix4d piecewise_function_evaluator::evaluate(double u) const {
+    // assume monotonic evaluation and store last evaluated segment
+    if (current_span_fn_ == nullptr || (u < current_span_start_ || current_span_end_ < u)) {
+        // there isn't a current span or u is outside the range of the current span
+        // get a new "current span"
+        std::tie(current_span_start_, current_span_end_, current_span_fn_) = get_span(u);
+    }
+
+    u -= current_span_start_; // make u relative to start of span
+    return (*current_span_fn_)(u);
+}
+
+taxonomy::item::ptr piecewise_function_evaluator::evaluate(const std::vector<double>& dist) const {
+    std::vector<taxonomy::point3::ptr> polygon;
+    polygon.reserve(dist.size());
+    for (auto& u : dist) {
+        Eigen::Matrix4d m = evaluate(u);
+        polygon.push_back(taxonomy::make<taxonomy::point3>(m(0, 3), m(1, 3), m(2, 3)));
+    }
+
+    return polygon_from_points(polygon);
+}
+
+std::tuple<double, double, const std::function<Eigen::Matrix4d(double u)>*> piecewise_function_evaluator::get_span(double u) const {
+    // force u to be within bounds of the curve
+    double s = pwf_->start();
+    double e = pwf_->end();
+    u = std::max(s, u);
+    u = std::min(u, e);
+
+    double span_start = s;
+    for (auto& [length, fn] : pwf_->spans()) {
+        double span_end = span_start + length;
+        auto tolerance = settings_.get<ifcopenshell::geometry::settings::Precision>().get();
+        if (span_start <= u && u < span_end + tolerance) {
+            return {span_start, span_end, &fn};
+        }
+        span_start += length;
+    }
+
+    Logger::Error("piecewise_function_impl::get_span span not found.");
+    return {0, 0, nullptr};
+}
diff --git a/src/ifcgeom/piecewise_function_evaluator.h b/src/ifcgeom/piecewise_function_evaluator.h
new file mode 100644
index 0000000000..ca1bddce54
--- /dev/null
+++ b/src/ifcgeom/piecewise_function_evaluator.h
@@ -0,0 +1,58 @@
+#ifndef ITERATOR_PWF_EVALUATOR_H
+#define ITERATOR_PWF_EVALUATOR_H
+
+#include "../ifcgeom/taxonomy.h"
+
+#include <boost/function.hpp>
+
+namespace ifcopenshell { namespace geometry {
+
+/// @brief utility class to evaluate piecewise_function objects
+class piecewise_function_evaluator {
+  public:
+    piecewise_function_evaluator(taxonomy::piecewise_function::const_ptr pwf, ifcopenshell::geometry::Settings* settings=nullptr);
+
+    /// @brief returns a vector of "distance along" points where the evaluate function computes loop points
+    std::vector<double> evaluation_points() const;
+
+    /// @brief returns a vector of "distance along" points between ustart and uend
+    /// @param ustart starting location
+    /// @param uend ending location
+    /// @param nsteps number of steps to evaluate
+    std::vector<double> evaluation_points(double ustart, double uend, unsigned nsteps) const;
+
+    /// @brief evaluates the piecewise function between start and end
+    /// evaluation point step size is taken from the settings object
+    taxonomy::item::ptr evaluate() const;
+
+    /// @brief evaluates the piecewise function between ustart and uend
+    /// if ustart and uend are out of range, the range of values evaluated
+    /// are constrained to start_ and start_+length_
+    /// @param ustart starting location
+    /// @param uend ending location
+    /// @param nsteps number of steps to evaluate
+    /// @return taxonomy::loop::ptr
+    taxonomy::item::ptr evaluate(double ustart, double uend, unsigned nsteps) const;
+
+    /// @brief evaluates the piecewise function at u
+    /// @param u u is constrained to be between start_ and start_+length
+    /// @return 4x4 placement matrix
+    Eigen::Matrix4d evaluate(double u) const;
+
+  private:
+    taxonomy::item::ptr evaluate(const std::vector<double>& dist) const;
+    std::tuple<double, double, const std::function<Eigen::Matrix4d(double u)>*> get_span(double u) const;
+
+    taxonomy::piecewise_function::const_ptr pwf_;
+
+    ifcopenshell::geometry::Settings settings_;
+
+    mutable double current_span_start_ = 0;
+    mutable double current_span_end_ = 0;
+    mutable const std::function<Eigen::Matrix4d(double u)>* current_span_fn_ = nullptr;
+    mutable boost::optional<std::vector<double>> eval_points_;
+};
+
+}}
+
+#endif
\ No newline at end of file
diff --git a/src/ifcgeom/piecewise_function_impl.cpp b/src/ifcgeom/piecewise_function_impl.cpp
index ecd2762057..6fa29fb649 100644
--- a/src/ifcgeom/piecewise_function_impl.cpp
+++ b/src/ifcgeom/piecewise_function_impl.cpp
@@ -7,97 +7,40 @@ namespace geometry {
 
 namespace taxonomy {
 
-std::vector<double> ifcopenshell::geometry::taxonomy::piecewise_function_impl::evaluation_points() const {
-    if (!eval_points_.has_value()) {
-        double curve_length = length();
+piecewise_function_impl::piecewise_function_impl(double start, const spans_t& s) : start_(start), spans_(s) {
+}
 
-        auto param_type = settings_ ? settings_->get<ifcopenshell::geometry::settings::PiecewiseStepType>().get() : ifcopenshell::geometry::settings::PiecewiseStepMethod::MAXSTEPSIZE;
-        auto param = settings_ ? settings_->get<ifcopenshell::geometry::settings::PiecewiseStepParam>().get() : 0.5;
-        unsigned num_steps = 0;
-        if (param_type == ifcopenshell::geometry::settings::PiecewiseStepMethod::MAXSTEPSIZE) {
-            // parameter is max step size
-            num_steps = (unsigned)std::ceil(curve_length / param);
-        } else {
-            // parameter is minimum number of steps
-            num_steps = (unsigned)std::ceil(param);
-        }
-
-        eval_points_ = evaluation_points(start_, start_ + curve_length, num_steps);
+piecewise_function_impl::piecewise_function_impl(double start, const std::vector<piecewise_function::ptr>& pwfs) : start_(start) {
+    for (auto& pwf : pwfs) {
+        spans_.insert(spans_.end(), pwf->spans().begin(), pwf->spans().end());
     }
-    return *eval_points_;
 }
 
-std::vector<double> ifcopenshell::geometry::taxonomy::piecewise_function_impl::evaluation_points(double ustart, double uend, unsigned nsteps) const {
-    double curve_length = length();
-    ustart = std::max(start_, ustart);
-    uend = std::min(uend, start_ + curve_length);
+const piecewise_function_impl::spans_t& piecewise_function_impl::spans() const { return spans_; }
 
-    nsteps = std::max(1u, nsteps); // never have fewer than 1 step
+bool piecewise_function_impl::is_empty() const { return spans_.empty(); }
 
-    auto resolution = (uend - ustart) / nsteps;
-
-    std::vector<double> u_values;
-    u_values.reserve(nsteps);
-
-    for (unsigned i = 0; i <= nsteps; ++i) {
-        auto u = resolution * i + ustart;
-        u_values.push_back(u);
-    }
-
-    return u_values;
+double piecewise_function_impl::start() const {
+    return start_;
 }
 
-ifcopenshell::geometry::taxonomy::item::ptr ifcopenshell::geometry::taxonomy::piecewise_function_impl::evaluate() const {
-    return evaluate(evaluation_points());
+double piecewise_function_impl::end() const {
+    return start_ + length();
 }
 
-item::ptr ifcopenshell::geometry::taxonomy::piecewise_function_impl::evaluate(double ustart, double uend, unsigned nsteps) const {
-    return evaluate(evaluation_points(ustart, uend, nsteps));
+double piecewise_function_impl::length() const {
+    return std::accumulate(spans_.begin(), spans_.end(), 0.0, [](const auto& v, const auto& s) { return v + s.first; });
+
+    // this is a secondary option where we only compute length once and cache it.
+    // mutex is needed to prevent interruption of the accumulation if there is multi-threading
+    // skipping this detail for now and just adding up the span lengths every time
+    //if (!length_.has_value()) {
+    //    length_ = std::accumulate(spans_.begin(), spans_.end(), 0.0, [](const auto& v, const auto& s) { return v + s.first; });
+    //}
+    //return *length_;
 }
 
-item::ptr ifcopenshell::geometry::taxonomy::piecewise_function_impl::evaluate(const std::vector<double>& dist) const {
-    std::vector<taxonomy::point3::ptr> polygon;
-    polygon.reserve(dist.size());
-    for (auto& u : dist) {
-        Eigen::Matrix4d m = evaluate(u);
-        polygon.push_back(taxonomy::make<taxonomy::point3>(m.col(3)(0), m.col(3)(1), m.col(3)(2)));
-    }
-
-    return polygon_from_points(polygon);
-}
-
-Eigen::Matrix4d ifcopenshell::geometry::taxonomy::piecewise_function_impl::evaluate(double u) const {
-    // assume monotonic evaluation and store last evaluated segment
-    if (current_span_fn_ == nullptr || (u < current_span_start_ || current_span_end_ < u)) {
-        // there isn't a current span or u is outside the range of the current span
-        // get a new "current span"
-        std::tie(current_span_start_, current_span_end_, current_span_fn_) = get_span(u);
-    }
-
-    u -= current_span_start_; // make u relative to start of span
-    return (*current_span_fn_)(u);
-}
-
-std::tuple<double, double, const std::function<Eigen::Matrix4d(double u)>*> ifcopenshell::geometry::taxonomy::piecewise_function_impl::get_span(double u) const {
-    // force u to be within bounds of the curve
-    double s = start();
-    double e = end();
-    u = std::max(s, u);
-    u = std::min(u, e);
-
-    double span_start = s;
-    for (auto& [length, fn] : spans_) {
-        double span_end = span_start + length;
-        auto tolerance = settings_ ? settings_->get<ifcopenshell::geometry::settings::Precision>().get() : 0.001;
-        if (span_start <= u && u < span_end + tolerance) {
-            return {span_start, span_end, &fn};
-        }
-        span_start += length;
-    }
-
-    Logger::Error("piecewise_function_impl::get_span span not found.");
-    return {0, 0, nullptr};
-}
+piecewise_function_impl* piecewise_function_impl::clone_() const { return new piecewise_function_impl(*this); }
 
 } // namespace taxonomy
 
diff --git a/src/ifcgeom/piecewise_function_impl.h b/src/ifcgeom/piecewise_function_impl.h
index 0c2f306ac5..daf8636feb 100644
--- a/src/ifcgeom/piecewise_function_impl.h
+++ b/src/ifcgeom/piecewise_function_impl.h
@@ -12,79 +12,23 @@ namespace taxonomy {
 struct piecewise_function_impl {
     using spans_t = std::vector<std::pair<double, std::function<Eigen::Matrix4d(double u)>>>;
 
-    piecewise_function_impl(double start, const spans_t& s, ifcopenshell::geometry::Settings* settings = nullptr) : start_(start),
-                                                                                                                  settings_(settings),
-                                                                                                                  spans_(s){};
-    piecewise_function_impl(double start, const std::vector<piecewise_function::ptr>& pwfs, ifcopenshell::geometry::Settings* settings = nullptr) : start_(start),
-                                                                                                                                                    settings_(settings) {
-        for (auto& pwf : pwfs) {
-            spans_.insert(spans_.end(), pwf->spans().begin(), pwf->spans().end());
-        }
-    };
+    piecewise_function_impl(double start, const spans_t& s);
+    piecewise_function_impl(double start, const std::vector<piecewise_function::ptr>& pwfs);
     piecewise_function_impl(piecewise_function_impl&&) = default;
     piecewise_function_impl(const piecewise_function_impl&) = default;
 
-    const ifcopenshell::geometry::Settings* settings_ = nullptr;
-
-    const spans_t& spans() const { return spans_; }
-
-    bool is_empty() const { return spans_.empty(); }
-
-    double start() const {
-        return start_;
-    }
-
-    double end() const {
-        return start_ + length();
-    }
-
-    double length() const {
-        if (!length_.has_value()) {
-            length_ = std::accumulate(spans_.begin(), spans_.end(), 0.0, [](const auto& v, const auto& s) { return v + s.first; });
-        }
-        return *length_;
-    }
-
-    piecewise_function_impl* clone_() const { return new piecewise_function_impl(*this); }
-
-    /// @brief returns a vector of "distance along" points where the evaluate function computes loop points
-    std::vector<double> evaluation_points() const;
-
-    /// @brief returns a vector of "distance along" points between ustart and uend
-    /// @param ustart starting location
-    /// @param uend ending location
-    /// @param nsteps number of steps to evaluate
-    std::vector<double> evaluation_points(double ustart, double uend, unsigned nsteps) const;
-
-    /// @brief evaluates the piecewise function between start and end
-    /// evaluation point step size is taken from the settings object
-    item::ptr evaluate() const;
-
-    /// @brief evaluates the piecewise function between ustart and uend
-    /// if ustart and uend are out of range, the range of values evaluated
-    /// are constrained to start_ and start_+length_
-    /// @param ustart starting location
-    /// @param uend ending location
-    /// @param nsteps number of steps to evaluate
-    /// @return taxonomy::loop::ptr
-    item::ptr evaluate(double ustart, double uend, unsigned nsteps) const;
-
-    /// @brief evaluates the piecewise function at u
-    /// @param u u is constrained to be between start_ and start_+length
-    /// @return 4x4 placement matrix
-    Eigen::Matrix4d evaluate(double u) const;
+    const spans_t& spans() const;
+    bool is_empty() const;
+    double start() const;
+    double end() const;
+    double length() const;
+    piecewise_function_impl* clone_() const;
 
   private:
-    item::ptr evaluate(const std::vector<double>& dist) const;
-    std::tuple<double, double, const std::function<Eigen::Matrix4d(double u)>*> get_span(double u) const;
     double start_ = 0.0; // starting value of the pwf
     spans_t spans_;
 
-    mutable double current_span_start_ = 0;
-    mutable double current_span_end_ = 0;
-    mutable const std::function<Eigen::Matrix4d(double u)>* current_span_fn_ = nullptr;
-    mutable boost::optional<double> length_;
-    mutable boost::optional<std::vector<double>> eval_points_;
+    //mutable boost::optional<double> length_; // used for length() method
 };
 
 } // namespace taxonomy
diff --git a/src/ifcgeom/taxonomy.cpp b/src/ifcgeom/taxonomy.cpp
index 9b4f5043aa..1dd61d72b0 100644
--- a/src/ifcgeom/taxonomy.cpp
+++ b/src/ifcgeom/taxonomy.cpp
@@ -464,12 +464,12 @@ ifcopenshell::geometry::taxonomy::solid::ptr ifcopenshell::geometry::create_box(
 }
 
 ///////////////////
-piecewise_function::piecewise_function(double start, const spans_t& s, ifcopenshell::geometry::Settings* settings, const IfcUtil::IfcBaseInterface* instance) : implicit_item(instance) {
-    impl_ = new piecewise_function_impl(start, s, settings);
+piecewise_function::piecewise_function(double start, const spans_t& s, const IfcUtil::IfcBaseInterface* instance) : implicit_item(instance) {
+    impl_ = new piecewise_function_impl(start, s);
 }
 
-piecewise_function::piecewise_function(double start, const std::vector<piecewise_function::ptr>& pwfs, ifcopenshell::geometry::Settings* settings, const IfcUtil::IfcBaseInterface* instance) : implicit_item(instance) {
-    impl_ = new piecewise_function_impl(start, pwfs, settings);
+piecewise_function::piecewise_function(double start, const std::vector<piecewise_function::ptr>& pwfs, const IfcUtil::IfcBaseInterface* instance) : implicit_item(instance) {
+    impl_ = new piecewise_function_impl(start, pwfs);
 };
 
 piecewise_function::piecewise_function(const piecewise_function& other) : implicit_item(other) {
@@ -486,11 +486,6 @@ double piecewise_function::start() const { return impl_->start(); }
 double piecewise_function::end() const { return impl_->end(); }
 double piecewise_function::length() const {   return impl_->length(); }
 
-std::vector<double> piecewise_function::evaluation_points() const { return impl_->evaluation_points(); }
-std::vector<double> piecewise_function::evaluation_points(double ustart, double uend, unsigned nsteps) const { return impl_->evaluation_points(ustart, uend, nsteps); }
-item::ptr piecewise_function::evaluate() const { return impl_->evaluate(); }
-item::ptr piecewise_function::evaluate(double ustart, double uend, unsigned nsteps) const { return impl_->evaluate(ustart, uend, nsteps); }
-Eigen::Matrix4d piecewise_function::evaluate(double u) const { return impl_->evaluate(u); }
 
 ifcopenshell::geometry::taxonomy::collection::ptr ifcopenshell::geometry::flatten(const taxonomy::collection::ptr& deep) {
 	auto flat = make<taxonomy::collection>();
diff --git a/src/ifcgeom/taxonomy.h b/src/ifcgeom/taxonomy.h
index 3b77273240..db9c97863e 100644
--- a/src/ifcgeom/taxonomy.h
+++ b/src/ifcgeom/taxonomy.h
@@ -347,8 +347,6 @@ typedef item const* ptr;
 			struct implicit_item : public geom_item {
 				DECLARE_PTR(implicit_item)
 				using geom_item::geom_item;
-
-				virtual item::ptr evaluate() const = 0;
 			};
 
 			struct piecewise_function_impl; // forward declaration
@@ -357,14 +355,12 @@ typedef item const* ptr;
 
 				using spans_t = std::vector<std::pair<double, std::function<Eigen::Matrix4d(double u)>>>;
 
-            piecewise_function(double start, const spans_t& s, ifcopenshell::geometry::Settings* settings = nullptr, const IfcUtil::IfcBaseInterface* instance = nullptr);
-            piecewise_function(double start, const std::vector<piecewise_function::ptr>& pwfs, ifcopenshell::geometry::Settings* settings = nullptr, const IfcUtil::IfcBaseInterface* instance = nullptr);
+            piecewise_function(double start, const spans_t& s, const IfcUtil::IfcBaseInterface* instance = nullptr);
+            piecewise_function(double start, const std::vector<piecewise_function::ptr>& pwfs, const IfcUtil::IfcBaseInterface* instance = nullptr);
             piecewise_function(piecewise_function&&) = default;
             piecewise_function(const piecewise_function&);
             virtual ~piecewise_function();
 
-				const ifcopenshell::geometry::Settings* settings_ = nullptr;
-
 				const spans_t& spans() const;
 				bool is_empty() const;
 				double start() const;
@@ -379,33 +375,6 @@ typedef item const* ptr;
 					return boost::hash<decltype(v)>{}(v);
 				}
 
-				/// @brief returns a vector of "distance along" points where the evaluate function computes loop points
-				std::vector<double> evaluation_points() const;
-
-				/// @brief returns a vector of "distance along" points between ustart and uend
-            /// @param ustart starting location
-            /// @param uend ending location
-            /// @param nsteps number of steps to evaluate
-            std::vector<double> evaluation_points(double ustart, double uend, unsigned nsteps) const;
-
-            /// @brief evaluates the piecewise function between start and end
-				/// evaluation point step size is taken from the settings object
-            item::ptr evaluate() const override;
-
-            /// @brief evaluates the piecewise function between ustart and uend
-				/// if ustart and uend are out of range, the range of values evaluated
-				/// are constrained to start_ and start_+length_
-            /// @param ustart starting location
-            /// @param uend ending location
-            /// @param nsteps number of steps to evaluate
-            /// @return taxonomy::loop::ptr
-            item::ptr evaluate(double ustart, double uend, unsigned nsteps) const;
-
-				/// @brief evaluates the piecewise function at u
-				/// @param u u is constrained to be between start_ and start_+length
-				/// @return 4x4 placement matrix
-				Eigen::Matrix4d evaluate(double u) const;
-
             private:
 				    // note: it would be better if this were a std::unique_ptr, but that requires having the full definition
 					 // of piecewise_function_impl in this header file, which defeats the purpose of the PIMPL idiom.
diff --git a/src/ifcwrap/IfcGeomWrapper.i b/src/ifcwrap/IfcGeomWrapper.i
index 0f26e28db7..2b2178e125 100644
--- a/src/ifcwrap/IfcGeomWrapper.i
+++ b/src/ifcwrap/IfcGeomWrapper.i
@@ -246,6 +246,7 @@ namespace {
 %include "../ifcgeom/Iterator.h"
 %include "../ifcgeom/GeometrySerializer.h"
 %include "../ifcgeom/taxonomy.h"
+%include "../ifcgeom/piecewise_function_evaluator.h"
 
 %include "../serializers/SvgSerializer.h"
 %include "../serializers/HdfSerializer.h"
diff --git a/src/ifcwrap/IfcPython.i b/src/ifcwrap/IfcPython.i
index b3b6cc3a85..f70388663d 100644
--- a/src/ifcwrap/IfcPython.i
+++ b/src/ifcwrap/IfcPython.i
@@ -84,6 +84,7 @@
 %{
 	#include "../ifcgeom/Iterator.h"
 	#include "../ifcgeom/taxonomy.h"
+	#include "../ifcgeom/piecewise_function_evaluator.h"
 #ifdef IFOPSH_WITH_OPENCASCADE
 	#include "../ifcgeom/Serialization/Serialization.h"
 	#include "../ifcgeom/kernels/opencascade/IfcGeomTree.h"
@@ -159,6 +160,7 @@
 %module ifcopenshell_wrapper %{
 	#include "../ifcgeom/Converter.h"
 	#include "../ifcgeom/taxonomy.h"
+	#include "../ifcgeom/piecewise_function_evaluator.h"
 #ifdef IFOPSH_WITH_OPENCASCADE
 	#include "../ifcgeom/Serialization/Serialization.h"
 	#include "../ifcgeom/kernels/opencascade/IfcGeomTree.h"