Modular cabinetry is commonly found in lumberyards and building centers. These cabinets are built on 3" increments and there is no deviation from those measurements without a significant price increase in your cabinets. Cabinets built on 3" increments require the use of filler panels to "fill" the space where there is no actual cabinets. These filler panels waste space, are unsightly and waste valuable space.
RTA stands for Ready To Assemble. Cabinets from places like IKEA are RTA. The responsibility of assembly is placed on the homeowner or your contractor.
Gossling Woodworking prides itself in custom cabinetry which uses every inch of cabinet space thus providing 100% usable, functional cabinetry.