I finally decided to explore Blender 2.8 Beta (I still keep the 2.79) - in particular as I wanted to explore the GreasePencil object.
So far I suffer and struggle to get the workflow. In particular with the fill color function.
I draw a face outline and when I try to fill it, the color covers only portion of the surface.
I tried to check if the points are all located on the same surface (i.e. one axis is locked) - I didn't find the lock option. I work with Front X-Z, camera view. I repeated the sketch without touching the view to ensure that all points stay on the same plan, I still get erratic fill color.
I tried to go the Edit and Sculpt modes. Yet, it takes couple of hours to place every point at place.
I then created a new layer and wanted to use its alpha feature but it crashes constantly. I can only feel color if the strokes are on the same layers.
Thanks in advance for any input, advice to tackle the issue