Excel 2010 :: Calculating Coordinates For A Point On Multi-Segment 3D Line

Windows 8, Excel 2010

I have XYZ Coordinates for a continuous 3-D line that has numerous segments. I want to input a distance along that line, and have it create the XYZ coordinates at that point. See Image for reference.

Row 2 is my start point - I input the initial coordinates here - this point is the origin of the 3-D line
Column B is where I want the calculated Y value to go for each point
Column C is where I want the calculated X value to go
Column D is where I want the calculated Z Value to go
Column E is the how far along the 3-D line that the (to be calculated) point should be at. (MD1)
Columns G, H, & I are given to me, and I use this data to generate the coordinates in Columns J, K, & L
Column O is the cumulative length of the line at that coordinate. (MD2)

Basically, I had planned on writing a formula to:

Find the coordinates of the point who's MD2 (column O) is before the desired point's MD1 (column E)Find the coordinates of the point who's MD2 (column O) is after the desired point's MD1 (column E)Subtract MD's (column O) to get the length of the segmentFind the distance along that segment that MD1 (column E) fallsUse that distance to traverse along that line to the desired point.