diff --git a/python/raytracing/inside_viewer.py b/python/raytracing/inside_viewer.py
index e6670f49..9ab779f0 100644
--- a/python/raytracing/inside_viewer.py
+++ b/python/raytracing/inside_viewer.py
@@ -420,7 +420,7 @@ def create_skeleton_frame(self, parent):
 
         UniformDictController.create_horizontal_scale(
             frame,
-            self.widget.ui_uniform_dict,
+            self.widget.ui_parameter_dict,
             key='edgeThickness',
             title='Face boundary thickness',
             row=row,
@@ -440,7 +440,7 @@ def create_skeleton_frame(self, parent):
                 left_end=0.0,
                 right_end=1.25,
                 update_function=self.widget.recompute_raytracing_data_and_redraw,
-                format_string='%.2f'))
+                format_string='%.3f'))
         row += 1
 
         self.edgeTubeRadiusController = (
@@ -452,7 +452,8 @@ def create_skeleton_frame(self, parent):
                 row=row,
                 left_end=0.0,
                 right_end=0.2,
-                update_function=self.widget.redraw_if_initialized))
+                update_function=self.widget.redraw_if_initialized,
+                format_string='%.3f'))
         row += 1
 
         label = ttk.Label(frame, text="Edge colors", padding=gui_utilities.label_pad)
diff --git a/python/raytracing/raytracing_view.py b/python/raytracing/raytracing_view.py
index ef535ccf..73b3caed 100644
--- a/python/raytracing/raytracing_view.py
+++ b/python/raytracing/raytracing_view.py
@@ -102,7 +102,6 @@ def __init__(self,
             'maxSteps' : ['int', 99 if has_weights else 40],
             'maxDist' : ['float', 6.5 if has_weights else 17.0],
             'subpixelCount': ['int', 1],
-            'edgeThickness' : ['float', 0.0000001],
 
             'contrast' : ['float', 0.1 if has_weights else 0.5],
             'noGradient' : ['bool', False],
@@ -121,6 +120,7 @@ def __init__(self,
         self.ui_parameter_dict = {
             'insphere_scale' : ['float', 0.0 ],
             'cuspAreas' : ['float[]', manifold.num_cusps() * [ 0.0 if has_weights else 1.0 ]],
+            'edgeThickness' : ['float', 0.0],
             'edgeTubeRadius' : ['float', 0.0 if has_weights else
                                 (0.025 if trig_type == 'finite' else 0.0)],
             'vertexRadius' : ['float', 0.0 if has_weights else 0.25],
@@ -194,6 +194,8 @@ def get_uniform_bindings(self, width, height):
                 'viewMode' : ('int', self.view),
                 'edgeTubeRadiusParam' :
                     ('float', math.cosh(self.ui_parameter_dict['edgeTubeRadius'][1]) ** 2 / 2.0),
+                'edgeThicknessParam' :
+                    ('float', math.sinh(self.ui_parameter_dict['edgeThickness'][1]) ** 2),
                 'vertexSphereRadiusParam' :
                     ('float', math.cosh(self.ui_parameter_dict['vertexRadius'][1]) ** 2)
             },
diff --git a/python/raytracing/shaders/fragment.glsl b/python/raytracing/shaders/fragment.glsl
index 70b38b5d..bb08db9f 100644
--- a/python/raytracing/shaders/fragment.glsl
+++ b/python/raytracing/shaders/fragment.glsl
@@ -35,7 +35,7 @@ uniform float currentWeight;
 uniform int maxSteps;
 uniform float maxDist;
 uniform int subpixelCount;
-uniform float edgeThickness;
+uniform float edgeThicknessParam;
 uniform float contrast;
 
 const int perspectiveTypeMaterial   = 0;
@@ -1034,11 +1034,11 @@ ray_trace_through_hyperboloid_tet(inout RayHit ray_hit)
     ray_hit.dist += atanh(smallest_p);
     advanceRayByDistParam(ray_hit.ray, smallest_p);
 
-    if(edgeThickness > 0.00001) {
+    if(edgeThicknessParam > 0.00001) {
         if (ray_hit.object_type == object_type_face) {
             if (!traceInsideVertexNeighborhood() ||
                 smallest_p > horosphere_exit_param) {
-                if(triangleBdryParam(ray_hit.ray.point, ray_hit.tet_num, ray_hit.object_index) < edgeThickness) {
+                if(triangleBdryParam(ray_hit.ray.point, ray_hit.tet_num, ray_hit.object_index) < edgeThicknessParam) {
                     ray_hit.object_type = object_type_edge_fan;
                 }
             }