@tig said: The error tells you the line and the file... Error: #<NoMethodError: undefined methodtransformation' for #Sketchup::Face:0x00000007b21748> C:/Users/tcw/AppData/Roaming/SketchUp/SketchUp 2016/SketchUp/Plugins/engineeringtoolbox_tools/engineeringtoolbox.rb:26:in eval' Line 26 in engineeringtoolbox.rb A Face does not have a transformation. So I suspect that the code [I don't have it at hand] for '4x3 Concentric Reducer' is expecting you to have selected something that does have a transformation - like a group, component_instance etc... Have you read the usage instructions ? http://sketchup.engineeringtoolbox.com/concentric-eccentric-reducers-to_28.html TIG, Your clear explanation provided the direction needed. I actually had read through the instructions which is why I drew a circle on the floor and selected its face to place the new component on the floor. Guided by your answer, I made the circle a group and the component insertion worked as expected. Thanks, AustinPowered