A rendering of the new Museum for African Art, with its soaring four-story wall, curved ceiling of rare Ghanaian wood and elaborate spiraling staircase, still sits on an easel in an unfinished concrete skeleton facing Central Park.

But those distinctive features and the $135 million budget that would have paid for them have now been shelved. After years of outsize promises and repeated postponements, officials now acknowledge that fund-raising travails have compelled them to scale back the grand design for the museum’s new home on Fifth Avenue.