Backface culling for wireframe drawing mode , why not available?!

A few things:

  • there is a retopology shading feature in development. The RCS proposal has the “in development” tag and I saw a few tasks on developer.blender.org about it (here’s one I could find back).

  • in the mean time, there are add-ons. Draw X-ray uses a shading method to put the geometry of the edited object “on top” of other objects using a distance threshold and Backface Hiding (made by yours truly) simply uses the face normals like backface culling does, except not in real-time but with the push of a button. Finally there’s Retopoflow which does a lot of things including a similar shading method to Draw-XRay. They all have their pros and cons and use cases. If you need the hiding feature but don’t need other retopo tools. In terms of pricing, Backface Hiding is completely free, Draw X-Ray is a “pay what you want” on Gumroad and Retopoflow is currently $86.