Hello @Ometecuthli ,
I see you’ve already gotten excellent tips from both @zber2 and @tobor8man. To add to what they have already said, and to apologize in case I go over ground that has already been covered, the geometry in your original file is problematic for ZRemesher.
From the screenshot, I assumed that your mesh was a single sided 2D surface. It is actually a closed volume, though flattened into a 2d form with no thickness. You can see this if you switch on Tool> Display> Double and Polyframe mode. There are actually two overlapping surfaces here, and the normals near the edge are twisted quite a bit. This is why you can’t get good definition on the edge.
Dynamesh outright wont work with a mesh that is overly thin or 2D. ZRemesher can work on 2D geometry, but tends not to like when two overlapping surfaces are smashed together, such as can sometimes happen with a tool like the Clip brush.
Furthermore, the edge of your volume is poorly defined, so ZRemesher is having trouble finding the form there. The edge of your shape is not defined by a continuous edge loop you can trace all the way around the shape, with a loop of extruded polygons in between the front and rear surfaces. In some areas the topology just sort of twists around underneath and creates a thin, ultrasharp, triangular edge shape.
For best results try to go one of two ways:
- Work on your surface as actual single sided 2D geometry.
If you use the ZModeler Alt key functionality to assign temporary polygroup to the polygons on top of your mesh, then Polygon > Extrude> with the “No sides” option enabled, you can extract the top section of your mesh as a single sided surface. Split or delete the unwanted geometry, and then use ZRemesher on the single sided surface. There are other ways to do this, but they will require masking, and masking the points on a squashed shape like that could be difficult.
It should now ZRemesh without issue. You can use the “Thickness” option with Dynamic Subdivision to preview the surface with a bit of virtual thickness until you are ready to convert the geometry to an actual closed volume.
- Work on your mesh as a well-defined 3d volume.
When you Extract a shape with thickness from a surface, as the Mesh Extract function would do by default, it should create a front and rear surface, separated by a nicely defined loop of polygons and creased edges. ZRemesher understands this very well, and it gives it the information to produce much better results, especially with ZRemesher options like “Keep Groups”.
Remember, if you try to ZRemesh a target mesh that is extremely low resolution, ZRemesher may pick up the polygon faceting and bake that into the resulting mesh. You’ll want the shape you are ZRemeshing to be subdivided sufficiently to produce smooth results. In order to keep the form accurate, you may wish to produce the target volume at higher resolution. Otherwise, when subdividing low poly geometry, it will require creasing to specify which edges stay crisp when smoothing.
Hope that helps a bit. Good luck! 
