An oasis, says one popular dictionary, is a refuge that can also ''provide relief from the usual.'' That is what Roland Dick of Insite Planners Inc. had in mind when he put together his ''ultimate hideaway'' for the recent Manhattan design showhouse of the International Society of Interior Designers.
It is a room that either stimulates or invites repose, depending on the mood electronically programmed for it by computer and cassette. In this particular setting, the cassette recording projects sounds of the jungle, the desert, and the city. The cassette tape also signals the computer, which controls light dimmers in the room. Without moving from the sofa, one can enjoy a series of sound-and-light mood changes in the room.
This program was set up by Mr. Dick to illustrate how the light in a room can be altered from a bright intensity to a soft, intimate glow, with appropriate accompanying music or sounds. ''We have found that when people entertain, they program everything but the mood of the room, '' he says. ''They program the menu , the linens, the dishes, glassware, and silver, but they fail to see the importance of programming subtle changes of lighting and background music as the evening progresses.
''Most people do not think of changes of mood and movement when they are decorating a room,'' the designer adds.
Besides the sound-and-light program for this room, Mr. Dick designed a circular sofa with many pillows, which rotates to take in whatever scene is desired - fireplace wall, television screen, or view of modern sculpture. The chair moves, too, and it also has five slipcovers in various colors. The hand-painted silk ''sails'' at the window also pivot easily.