diff --git a/soho/python2.7/PBRTnodes.py b/soho/python2.7/PBRTnodes.py
index d0a6a9b..9f2d768 100644
--- a/soho/python2.7/PBRTnodes.py
+++ b/soho/python2.7/PBRTnodes.py
@@ -382,7 +382,9 @@ def get_used_parms(self):
             if self.node.coshaderNodes(parm_name):
                 # Instead of adding checks for this multiple
                 # times, check once and then continue
-                parms[parm_name] = parm_tup
+                if not parm_tup.isHidden():
+                    # If hidden, then wrong signature
+                    parms[parm_name] = parm_tup
                 continue
 
             if parm_tup.isDisabled() or parm_tup.isHidden():
diff --git a/soho/python3.7/PBRTnodes.py b/soho/python3.7/PBRTnodes.py
index 8c61db5..1bf5bb4 100644
--- a/soho/python3.7/PBRTnodes.py
+++ b/soho/python3.7/PBRTnodes.py
@@ -380,7 +380,9 @@ def get_used_parms(self):
             if self.node.coshaderNodes(parm_name):
                 # Instead of adding checks for this multiple
                 # times, check once and then continue
-                parms[parm_name] = parm_tup
+                if not parm_tup.isHidden():
+                    # If hidden, then wrong signature
+                    parms[parm_name] = parm_tup
                 continue
 
             if parm_tup.isDisabled() or parm_tup.isHidden():
diff --git a/tests/scenes/TestMaterials/test_texture_mixing_material.pbrt b/tests/scenes/TestMaterials/test_texture_mixing_material.pbrt
new file mode 100644
index 0000000..1d391d6
--- /dev/null
+++ b/tests/scenes/TestMaterials/test_texture_mixing_material.pbrt
@@ -0,0 +1,52 @@
+
+Film "rgb" "string filename" [ "test_texture_mixing_material.exr" ] "integer xresolution" [ 320 ] "integer yresolution" [ 240 ]
+PixelFilter "gaussian" "float xradius" [ 2 ] "float yradius" [ 2 ]
+Sampler "zsobol" "integer pixelsamples" [ 16 ]
+Integrator "volpath" "integer maxdepth" [ 5 ]
+Accelerator "bvh"
+
+#  /obj/cam1
+Transform [ 0.6691 -0.4263 -0.6087 0 0 0.8192 -0.5736 0 -0.7431 -0.3838 -0.5481 0 0.5921 -0.07283 13.84 1 ]
+Camera "perspective" "float fov" [ 45 ] "float screenwindow" [ -1 1 -0.75 0.75 ]
+
+WorldBegin	# {
+
+    #  ==================================================
+    #  Light Definitions
+    #  /obj/envlight1
+    AttributeBegin	# {
+	Transform [ 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 ]
+	Scale 1 1 -1
+	Rotate 90 0 0 1
+	Rotate 90 0 1 0
+	LightSource "infinite" "float scale" [ 0.5 ]
+    AttributeEnd	# }
+
+
+    #  ==================================================
+    #  NamedMaterial Definitions
+    Texture "/mat/pbrt_texture_checkerboard2" "spectrum" "checkerboard"
+    Texture "/mat/pbrt_texture_checkerboard1" "float" "checkerboard"
+    Texture "/mat/pbrt_texture_mix1" "float" "mix" "float amount" [ 0.4 ] "texture tex1" [ "/mat/pbrt_texture_checkerboard1" ]
+    Texture "/mat/pbrt_texture_mix2" "spectrum" "mix" "texture amount" [ "/mat/pbrt_texture_mix1" ] "texture tex1" [ "/mat/pbrt_texture_checkerboard2" ]
+    MakeNamedMaterial "/mat/pbrt_material_diffuse1" "string type" "diffuse" "texture reflectance" [ "/mat/pbrt_texture_mix2" ]
+
+
+    #  ==================================================
+    #  NamedMedium Definitions
+
+    #  ==================================================
+    #  Object Instance Definitions
+
+    #  ==================================================
+    #  Object Definitions
+    #  --------------------------------------------------
+    #  /obj/geo1
+    AttributeBegin	# {
+	ConcatTransform [ 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 ]
+	NamedMaterial "/mat/pbrt_material_diffuse1"
+	#  Can not find soppath for object
+    AttributeEnd	# }
+
+
+	# }
diff --git a/tests/tests.py b/tests/tests.py
index 72f1e41..c6532c9 100644
--- a/tests/tests.py
+++ b/tests/tests.py
@@ -929,7 +929,7 @@ def test_exterior_cam(self):
 
     def test_exterior_cam_interior_obj(self):
         # TODO / NOTE:
-        # I don't believe this test is givign the expected results
+        # I don't believe this test is giving the expected results
         # as there is no mediums attached to the lights.
         # This is a lack of understanding on how pbrt-v4 works and
         # will require some experiments
@@ -1048,6 +1048,30 @@ def test_checker_material(self):
         self.geo.parm("shop_materialpath").set(matte.path())
         self.compare_scene()
 
+    def test_texture_mixing_material(self):
+        space = hou.node("/obj").createNode("null")
+        space.parmTuple("t").set([1, 2, 3])
+        space.parmTuple("s").set([5, 10, 20])
+        matte = hou.node("/mat").createNode("pbrt_material_diffuse")
+        checks_float = hou.node("/mat").createNode("pbrt_texture_checkerboard")
+        checks_spectrum = hou.node("/mat").createNode("pbrt_texture_checkerboard")
+        mix_float = hou.node("/mat").createNode("pbrt_texture_mix")
+        mix_spectrum = hou.node("/mat").createNode("pbrt_texture_mix")
+        checks_float.parm("signature").set("default")
+        checks_float.parm("dimension").set(2)
+        mix_float.parm("signature").set("default")
+        mix_float.parm("amount").set(0.4)
+        checks_spectrum.parm("signature").set("s")
+        checks_spectrum.parm("dimension").set(2)
+        mix_spectrum.parm("signature").set("s")
+        mix_spectrum.parm("amount").set(0.4)
+        mix_float.setNamedInput("tex1", checks_float, "output")
+        mix_spectrum.setNamedInput("tex1", checks_spectrum, "output")
+        mix_spectrum.setNamedInput("amount", mix_float, "output")
+        matte.setNamedInput("reflectance", mix_spectrum, "output")
+        self.geo.parm("shop_materialpath").set(matte.path())
+        self.compare_scene()
+
 
 class TestSpectrum(TestRoot):
     @classmethod