a mold apparatus and method for manufacturing panels having , as desired , one or more areas of reduced material comprising a facing sheet and integrally attached cell forming walls extending in roughly perpendicular fashion from the facing sheet . additionally , a method for molding panels , including large scale panels , from thermoplastic resins and other moldable materials requiring significantly less energy than other known molding methods , and providing for panels having one or more areas exhibiting continuous outer surfaces on all dimensions . a lower negative mold member has a plurality of upwardly facing positive standoffs defining interstitial channels into which thermoplastic resin or other moldable material is filled . a generally planar upper mold member is placed on the lower mold , and the combined mold assembly is then subjected to elevated heat and pressure , allowing said thermoplastic resin or other moldable material to melt within the interstitial spaces of the lower mold member . after cooling , upper and lower mold members are separated , and a molded panel structure is removed therefrom .