Jagged boundary edges

hi .
i have a car part from 3d scanning . i use rhino for designing some body kit on it . but i have problem with jagged boundary edges of my mesh . i want thay the outline (boundary) parts of my car be curve and clean but it has jugged triangles .
this is my work:

please help . thanks .


i am afraid the 3d scanning data resolution is low thats why meshes are like that.