As far as I know, PhysHit hitInfo; only return hitInfo.face (this is face id of source mesh)
How can I get the MaterialPtr of touched mesh of ray casting from this ?

i would look into doing this :

create a switch for phys_hit.group

case AG_X:
ClassX*t_classX = (ClassX*)phys_hit.obj;

from there you can do custom draw of material from your class or query the mesh and grab the material, tho not sure how you would query it if there is different meshpart to get the one touched, tho i am sure its possible

Yeah I want to get material on a specified mesh part of ray touch. There is a function to get material of a mesh part but no function to get mesh part from hitInfo.