problem/question with area or line chart for x axis

I need a 3d chart that will plot on the depth axes the series, on the category axis the position (-8 cm to + 8 cm) and on the z axis percent grow

Anyway, I can't get the x axis (category) to be linear (I have measured only at -8, -4, -2, -1, 1, 2, 4, 8 cm) but on the chart "-8" to "-4" is the same distance as "-4" to "-2" etc...how can I fix this?

Excel doesn't offer any kind of 3D scatter plot.

the only way to simulate the effect in Excel is to enter some "dummy point" to space the real points out properly. In your case, you'll need dummy points at +/-7,+/-6,+/-5, +/3, 0.

Either that or use a different graphing program that allows for 3D scatter plots. I don't do 3D plots, so I don't have any specific recommendations.