In this beginner tutorial jayanam explains how to get started with retopology in Blender 2.9.
He doesnt use popular retopo addons like F2 or Retopoflow, just one addon called Draw X-Ray to display the retopo mesh above the high poly mesh.
He starts the process with a simple plane and then enables snapping to faces for the retopo mesh. After that he uses the polybuild tool to snap vertices to the faces of the high poly mesh and also extrude new geometry to build the retopo mesh.
Another great feature is Auto merge which can be enabled in the Tool panel:
It very useful to automatically merge vertices when you bring them close together – the threshhold option defines in which range the merge will be applied.
Also a shrinkwrap modifier is added, so that the mesh is snapped to the underlying highpoly mesh as well, when for instance new geometry is extruded:
In the next part Jay will do the UV unwrapping (will be very simple) and then bring the retopo mesh to Substance Painter for texturing.