Outlines Only plug-in, Marker Outlines group
Marker Outlines produces an ‘etch-a-sketch’ sort of look with squiggly lines following the edge detection made by the Outlines Only plug-in.
Marker checkbox
Turned off by default. Turning this option on will activate the Marker controls. This produces an effect of squiggly lines using the global Outline Color and Background Color controls. Turning off the Marker checkbox will give you standard Outlines Only edge detection.
Flatness
Flatness determines the extent of the edges in the image. It produces larger or smaller regions of similar or single colors.
Default setting is 5. Value range is 0 to 30. The higher the Flatness, the fewer gradations you’ll see and the larger the regions of outlines will be. This means that each ‘cell’ (a region that is surrounded by an outline) will get larger. Lower Flatness values will produce more cells and more detail.
Simplicity
Simplicity controls the amount of edge detail in the image. The higher this is, the less detail you’ll be able to see.
Default setting is 5. Value range is 0 to 25. Lower Simplicity gives more edge detail and smaller outline fields. The higher the Simplicity, the more 'simple' the outline fields are. This means that less detail will be shown, which results in larger cells or regions.
Simplicity works in conjunction with Flatness. When Simplicity and Flatness are high, there is less outline detail (Simplicity) and larger outline fields (Flatness). When Simplicity and Flatness are lower, there are smaller, more detailed fields of outlines. When Simplicity is lower than Flatness, then more detail gets etched into the broader outline field. When Flatness is lower than Simplicity, then the outline fields are smaller and less detailed.
Separation
This is the most direct way of changing the Marker cell size.
Default setting is 8. Value range is 1 to 30. Lower values cause smaller cells, higher values cause larger cells. Separation works in tandem with Flatness and Simplicity to control the cell size.
Thickness
This sets the thickness of the Marker outlines. Default setting is 3. Value range is 1 to 30. Higher values mean thick lines. Depending upon your image, higher values will generate so much outlines that the underlying image will get covered.
Minimum Difference
This is really the most interesting control for Marker Outlines. This will cause the cells to be densely arrayed creating that Stained Glass look. Use Flatness and Simplicity to get larger cells.
Default setting is 10. Value range is 1 to 20. To get very distinct cells, set this to 1 or 2. Higher values result in outlines going off in random directions, producing an etch-a-sketch look. Very much like not-quite-random, modern-art scribbling. A large Minimum Difference can create a chaotic line drawing.
Antialias
Antialias is a percentage slider for the final output that helps to tone down any jagged edges. Default value is 50%. Value range is 0 to 100.
An Antialias setting of 0% is very slightly faster, but otherwise the render speed is the same as at higher values. Sometimes Antialias of 100% can look a bit blurry. If this is the case, just lower the value a bit.
Transparency
This sets the opacity level of the Marker effect. The default is 0%, which is fully transparent. Value range is from 0 to 100. The higher the value, the more transparent the Marker outlines are. The lower the value, the more opaque they are.