There is an object with no extrusion on first layer  

stl ziped

spiderwebmanifold

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Hi Greatspud

Was the model drawn in Inches? or was it really small? 

when I tries to load it, the slicer suggested converting to millimeters.   and the model ended up too large. 

So I resized it to fit my Prusa Mk3S

when I sliced it, with a 0.4mm nozzle, the model disappeared

so I tried slicing with a 0.25mm nozzle, and I got very thin traces... 

I reset to 0.4mm nozzle again, and changed the XY Size Compensation value to 0.1, and I can again now see traces... 

I have just thought that I could have turned off elephants foot compensation, 

No, that didn't work... 

Please find attached a project file, for your model with the XY Size Compensation set to 0.1mm   this causes the threads to be seen... 

regards Joan

Cool thanks. Ill try it. Now I know what to tinker with/I understand a little more Thanks

Cool thanks. Ill try it. Now I know what to tinker with/I understand a little more Thanks

Humm?

Is there a better way to model, to make the printer print fine lines?

more info

Model FULL SIZE, in Millimeters, and make sure that the line widths are the same size as, or thicker than the extrusion width for the layers involved. 

As standard the first layer extrusion width is 0.42mm with a 0.4mm nozzle
as standard other extrusion widths are 0.45 with a 0,4mm Nozzle 

the values are in the list above... 

note Elephant's foot Compensation, this artificially makes the first layer  elements, narrower. 
XY Size Compensation artificially makes the model larger on all layers 

If the model element is thinner than the extrusion width, the slicer will simply ignore that section

regards Joan