Dental Mesh Offset Algorithm Development

I need an algorithm that takes a dental model in STL format, recognises a closed margin line already present on the surface, and then carries out three sequential operations: 1. Margin definition & trimming... (Budget: €250 - €750 EUR, Jobs: 3D CAD, 3D Design, 3D Modelling, 3D Printing, 3D Rendering, 3D Visualization, Algorithm, Computer Graphics)