This vb Component for Grasshopper takes three edge length and produces the corresponding triangle.  This particular function begins with the first edge being aligned to the x axis of the world top in Rhino and produces the geometry so long as the three input numbers are valid to create a triangle. The component has been updated to work on a user specified plane.
INPUT Curve Item C Open or closed mesh
INPUT Double Item D The distance to be offset in the positive and negative.
INPUT Plane Item P Offset solution plane.
INPUT Integer Item V Corner style for offset kinks. [0 = none, 1 = sharp, 2 = round, 3 = smooth, 4 = chamfer]
INPUT Double Item T The offset or fitting tolerance.
OUTPUT Curve List S The shorter of the offset curve or curve sets
OUTPUT Curve List L The longer of the offset curve or curve sets
gha | Download User Objects
gh | Download Grasshopper Sample Files
Platform | Rhino 5, Grasshopper
Version | Grasshopper 0.9.0075
Type | Visual Basic Component