Can I use the shoe last technique with modifiers or constraints in Blender? I want to use the shoe last technique used in shoe making in Blender.
Please see the picture below.  



Curved plates and spheres overlap.
The curved plate is like shoe last, and I want to sculpt the sphere.  

I tried the following steps.  


With the shrinkwrap modifier, the sphere sticks to the curved plate and acts like a shoe last.
However, when attempting to sculpt, the sphere will stick to the curved plate and remain flat.  





Removing the shrinkwarp modifier enables free sculpting.  





But now the sphere passes through the curved plate.  




From the example above the specific features of the technique i want are as follows.  


When the mesh of the sphere is outside the curved plate, free sculpting should be possible.  
If the mesh of the sphere digs into the inside of the curved plate, the movement of the vertices is limited.  
This is similar to the shrinkwrap modifier, floor constraint or limit location constraint.  
But it's not about the transformation of the object, it's about the interaction between meshes.  


Can I model or sculpt in the same way as above in Blender?
No not an option, currently its vertex orientated (and it can add vertexes as well) its not object orientated and i doubt that will get into blender

However what you might do in your case is paint masks and play with the strength of it.