The nth contour line or zone in a chart is normally not associated with the nth contour style in the Chart3DContourStyles collection. The relationship between distribution levels (contour lines/zones) and the Chart3DContourStyles collection is as follows:

• If nstyles contour styles are provided, and the number of distribution levels is nlevels, the index of the contour style associated with the nth distribution level is the largest integer less than or equal to the following:
  (n * (nstyles - 1) / nlevels) + 1

For example, if one hundred contour styles and six distribution levels are defined, the distribution levels use the 1st, 21st, 41st, 60th, 80^th, and 100th elements of the Chart3DContourStyles collection, respectively. (The number of distribution levels is specified by the NumLevels property of the Chart3DContour object.)

To force a one-to-one match up between contour styles and distribution levels create an array of contour styles with the same number of elements as there are distribution levels. (If it is specified that zone regions be drawn, the array of contour styles must contain one more element than the number of distribution levels. Setting the IsZoned property of the Chart3DContour object to True specifies zone regions. The extra contour style is used to specify the last zone's fill color.)