  In view of a possible extension of the forward CMS muon detector system and
future LHC luminosity upgrades, Micro-Pattern Gas Detectors (MPGDs) are an
appealing technology. They can simultaneously provide precision tracking and
fast trigger information, as well as sufficiently fine segmentation to cope
with high particle rates in the high-eta region at LHC and its future upgrades.
We report on the design and construction of a full-size prototype for the CMS
endcap system, the largest Triple-GEM detector built to-date. We present
details on the 3D modeling of the detector geometry, the implementation of the
readout strips and electronics, and the detector assembly procedure.
