The gm_construct_hdr.zip file you have requested: Garry's Mod / Maps / Half-Life 2: Garry's Mod: Construct Map with HDR - 4.75mb is not available. Perhaps try browsing all files for the game Half-Life 2 and upload any files you want to share or are missing. This is the only information we could locate:
Molotov has recompiled the gm_construct map to add HDR lighting. He has also added a green room and the fixed the water to be less tiled.Grab it below.Very nice !