If you are going to use the Snap to Contour, you might want to adjust…
Vectorworks Tip 334 – Adjust the Site Model Settings to Make Snapping Easier (2)
If you are going to use the Snap to Contour, you might want to adjust the Site Model Settings to give you the correct contour to snap to. The second method is to adjust the Start Contour Offset to change the elevation of all of the contours .