When I make a stroke using the pen tool in Corel Painter 2018, a new layer is automatically generated. I found no apparent way to fix it. Is there a way to avoid it?
I don't use Corel Painter, however as in other similar applications, the "Pen Tool" is used for making vectors, which are different from normal strokes you would make with the Brush tool.
The Corel Painter documentation on the Pen tool is here
What this means is that each vector path you make with the Pen tool is a separate object with a stroke and fill. Each of these generates its own layer, so that the object is still editable. This is normal and how the tool is supposed to work. It works similarly in other applications which also have a Pen tool.
If you don't want that to happen, then perhaps ultimately, the Pen tool is not what you really need. Perhaps you would be better using the Brush tool to paint with.
Also note that when you export your art as a JPEG or PNG, when you have finished creating your work, all the vector layers in your Corel document will be flattened and rasterized anyway.
The Pen brushes should not operate like this, but several of the specialized brushes introduced in Corel Painter 2018, such as the Think Paint tool do create new layers. When messing around with random brushes, it's not uncommon for my to wind up with a half a dozen new layers as I switch types.
I currently have Corel Painter 2019 installed, but switching to the 2018 brushes, these categories seem to start their own layer if you switch to them, or to another one (other than, perhaps, erasers):
- Liquid Ink
- Thick Paint
- Real Watercolor
Also, in some of the categories, there will be watercolor, ink, etc brushes that create this effect.