First layer width does exactly what it sounds like - it adjusts the width of the extrusions used for the first layer. If the extrusions are wider, they will need to be further spaced apart as well. This is very easy to verify in the preview. Just change first layer width to 200% and you will see that they are spaced twice as far apart.
1. First Layer Height <100% does not reduce extrusion amount accordingly (i.e., it will produce a somewhat "squashed" first layer);
2. First Layer Height >100% does increase extrusion amount accordingly (i.e., will produce a taller, but not squashed first layer);
3. First Layer Width >100% increases extrusion amount and line spacing accordingly (i.e., will produce wider, but also wider spaced first layer lines).
For all, who need a precise first layer and want to print small details in the range of <1mm, e.G. small letters of a name plate filled with another colour and you don't see any details in your print....:
First check if your Extrusion multiplier (tab Extruder) is ok for the other layers, no over or under extrusion? If not, correct it....
Then check the first layer settings:
Open your profile, open tab called Layer, you have to deal with:
First Layer Hight ( start with 100%)
First Layer Width ( start with 100%)
First Layer Speed ( start with 40%)
Start a print of just the first layer.
You see too much plastic, no details, a rough surface?
Increase the distance between the bed and the nozzle:
(Level the bed a bit lower) or
Modify the z offset of your printer firmware or
Modify the Start G code script under the tab Scripts in the profile
Make a few test prints with different Z offsets and take the best...
You see ropes of plastic separated from each other
reduce layer hight till it fits or
level the bed a bit closer to the nozzle
Modify the z offset of your printer firmware or
Modify the Start G code script under the tab Scripts in the profile
Check if the Speed has an influence on the result. Does 10% First layer speed looks much better?
Unfortunately there seems no other way in S3D to correct over extrusion just for the first layer or did I miss something? It took me hours to understand that........
Maybe this is helpful for someone.....