By Adam Nagy
The equation curve values are fully accessible from the API and can be changed as well. One thing that can be difficult to spot, unless you read the API Help Reference carefully, is that the parameters for GetEquation and SetEquation are not the same. So if you try to use the same parameters then SetEquation will fail.
The difference is in the MinValue and MaxValue. In GetEquation they are Parameter, but in SetEquation they are a Variant which should either be a numeric value or a string.
This is how I can change the X value from "136*t" to "136+13.325*t^2"
Sub ModifyEquationCurve() Dim doc As PartDocument Set doc = ThisApplication.ActiveDocument Dim s3d As Sketch3D Set s3d = doc.ComponentDefinition.Sketches3D(1) Dim sec As SketchEquationCurve3D Set sec = s3d.SketchEquationCurves3D(1) Call s3d.Edit Dim x As String, y As String, z As String Dim cst As CoordinateSystemTypeEnum Dim min As Parameter, max As Parameter Dim mins As String, maxs As String Call sec.GetEquation(cst, x, y, z, min, max) mins = min.Expression maxs = max.Expression x = "136+13.625*t^2" Call sec.SetEquation(cst, x, y, z, mins, maxs) Call s3d.ExitEdit End Sub