Slope / Invert Lisp Routine?

I am very new to writting lisp routines and wondered if any one had similar routines that measured slope/invert type calculations based on distance...... this is to determine the invert elevation of a building sewer drainage system for coodination with civil engineers.

-It should be able to-

-ask user for starting point

- ask user for starting point elevation (i.e -18", -24" or -2' etc.)

- ask user for slope percentage (i.e. 1/8"/ft 1/4"/ft , 1/16"/ft

- ask user for next point

- multiply the distance between the two points by the % of slope and offer these options

-(end run/place ie/next point) default to next point

-end run would stop the command and place the calculated invert elev. (text) at a user selected point.

- next point would continue the command and add the total distances between all points selected and loop the options after each point is picked.

Then if there was a way to convert the fianl invert elevation into the following mtext format I.E. = XX'-XX" B.F.F. (invert elevation = Ft-inches below finish floor).

I know its a lot to ask, but i though if i mapped it out it might generate some similar lisp routines i could refer to for ideas and help on how to write it.

P.S. It could use a poly line command to draw a line from point to point.

"but i though if i mapped it out it might generate some similar lisp routines "

You're right; look at bottom of this page for related posts, there have been some invert lisp routines posted. Probably not quite the same as your request, though, but may find a starting point for modification.

I have some thing kinda similar, Will do rize/run from selecting a line. and then creates a little triangle with relavent data- i metric however.

Purhaps it could help you on your way?

regards

Flower

Riserun-V1.0.lsp