Project gp_Vec onto a surface to get gp_Vec2d

Hello,

when I have a vector in space (gp_Vec) and I want to project it onto a Geom_Surface/TopoDS_Face at a certain position, I have always done it like that:

- I have projected the position onto the surface with ShapeAnalysis_Surface::ValueOfUV.
- Then I have computed the vectors u and v spanning the tangent plane at this position with Geom_Surface::D1.
- At last I have computed the coordinates x and y such that x * u + y * v is the space vector projected onto the tangent plane at my position.

The according gp_Vec2d is then the vector with the two coordinates x and y.

I wonder whether it is necessary to do these computations on my own. Are there some OCC functions that do that? Perhaps optimized ones?

Thank you for your answers,
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