2d coordinate system with 3 axes

i am trying to establish a 2d-coordinate system with 3 axes (like RGB).
any ideas how to move a point along the axes of this system (maybe with 3 sliders)? the white numbers show the desired coordinates at the endpoints of the axes.

3_axes.gh (14.3 KB)

If you have 3 coordinates, one for each axis, you have a 3d system.

Pt(a, b, c) = axis1 * a + axis2 * b + axis3 * c

where the axes are normalized (have magnitude 1) and a, b and c are your coordinates that you can set with sliders.

But for your drawing, if you want space to be in that triangle, use barycentric coordinates.

great, thanks!