Have been working on a curve/line macro in microstation.
Here I tried to take Rhino average curve function into Microstation as an exercise to learn something about vba in microstation.
Vba is not necessary since similar could be achieved through lofting two curves and extracting its isocurves

Some thoughts on vba in microstation:
1. array difficult to work with (appending requires redim)
2. geometry have specific types with different properties i.e. lines/curves can be a complex chain with arc, bsplinecurve, line (line:3 polyline:4) or just one of the element types. Extra coding is required to determine if it is a complex chain and get its subelement, then the type of the subelement have to be checked.