The first of a half-dozen residential neighborhoods under construction as part of a master-planned Santa Clarita community will open to the public for the first time Saturday. Tri Pointe Homes Inc. of Irvine will have model homes open for touring in its anticipated Grayson development, consisting of 119 two-story detached homes. The development is the first phase of a master-planned community that will comprise nearly 500 homes on 250 acres of land located at Golden Valley and Newhall Ranch roads in Santa Clarita. The community, known as Five Knolls, is being developed by Canadian-based Brookfield Residential, which is also developing the Playa Vista commercial, retail and residential center in West Los Angeles. Along with Brookfield and Tri Pointe, residential homebuilders KB Home of Los Angeles, Christopher Homes of Newport Beach and Meritage Homes of Scottsdale, Ariz. will be developing neighborhoods at Five Knolls. The Grayson tract will offer three floor plans, with three to five bedrooms, and range from 2,000 to 2,400 square feet. Pricing will start in the $500,000 range. Two additional neighborhoods in the development are expected to begin sales later this summer.