Cascade Roman Blinds.

[Wingedharpy]

Anyone here an expert in maths and sewing?
I want to make a cascade roman blind but am tying myself up in knots regarding measurements for the baton placements.
As I go down the blind from top to bottom, the batons need to be placed further and further apart - to give the cascade effect when the blind is pulled up - but I have no clue where to start and some on line tools I have seen haven't really helped.
Anyone any good at this sort of thing, and, if so, if I provide the measurements, would you work it out for me?
TIA.

Help!

Step Two: Mark The Position Of The Dowels

Measure 5cm down from the top, and then, from this starting point, you will need to mark regular intervals down the length of the blind - these will be the positions of the dowels. These should be between 20cm and 30cm apart, finishing with a bottom section that is half the size of the rest. (For example, each interval is 20cm and the bottom interval is 10cm). Mark these intervals with tailors' chalk.
Found this on C4 website. Any good?

No, sorry Flossy, that wouldn't give the effect I'm after once the blinds are drawn up.
By spacing at regular intervals, as you've described, when pulled up, the folds/pleats will all sit together, back to back at the top of the blind.
I want them to sit about 1/2 way under the preceding one so that all the pleats are partly visible IYSWIM.
Hence, a cascade roman blind.
Thank you anyway for your reply.
I still haven't worked it out but I'm just going to cobble it together as best I can.
It won't be perfect but not much in the Wingedharpy household is!

I make roman blinds. For waterfalls you just need to use a soft tape measure or a length of something that is the finished drop that you want the blind to be. Start folding it from the top down, with each fold being lower than the one before. When you are happy with the folds then mark where the rods will be on the tape measure (with a pencil or pins) and then transfer this onto your fabric - after allowing for turnings at top and bottom.

Each set of folds need to increase by about 2/3", though exact measurments depend on what you have to play with

Have you tried this calculator from MyDecozo?