[UPDATED][DEPRECATED] Simplify3D: Confusing First Layer settings
/UPDATE:
Has has been pointed out, while this blog post was accurate many years ago, it no longer applies.
First Layer Height and Width:
Simplify3D 4.0 is a powerful 3D mesh slicer program for 3D printing with many options and settings, some of which are non-obvious. Such is the case with the First Layer Settings, under a process' Layer tab. Until I happened upon a post in Simplify3D's forums I didn't understand the effects of changing the First Layer Height and First Layer Width settings, causing me a lot of frustration and failed first layers.
First Layer Height:
Both nozzle height and extrusion amount can be affected by this setting, but perhaps not in the way you think.
If set below 100%:
Amount of extruded plastic is UNCHANGED.
Layer height (distance from nozzle to printing bed) is REDUCED
Values below 100% ONLY lower the nozzle closer to the printing surface. Essentially squishes the standard amount of plastic into a lower layer height.
This is meant to help with adhesion.
if set above 100%:
Amount of extruded plastic is INCREASED.
Layer height is INCREASED.
BOTH extrudes more plastic AND pulls the nozzle slightly away from bed so as not to squish the layer.
This is used primarily when printing fine layer heights and/or on slightly uneven printing beds. The extra height and plastic volume makes thin layers thicker and also helps smooth out bumps and inconsistencies in bed surfaces.
First Layer Width:
Width changes ALWAYS AFFECT extrusion amounts, but leave Layer Height UNCHANGED.
If set below 100%:
The amount of extruded plastic is REDUCED.
If set above 100%:
The amount of extruded plastic is INCREASED.
For reference, here's the full thread in Simplify3D's forums: https://forum.simplify3d.com/viewtopic.php?f=9&t=2292&start=20#p18419