dynamic stair block

Hey guys, Im trying to create a dynamic stair block as you can see in the attached drawing. the goal is to be able to stretch the stair up/down and be able to adjust the the riser height. the run always stays the same. But im having difficulties, can someone help out?

dynamic stair.dwg

It seems to work, but what difficulties are you having?

well if I stretch the stair, the diagonal lines dont line up. and if i adjust the stair riser only the first one changes, the rest move up with the stretch

Part of the diagonal line was included in the stretch. If it were not included, it would stay lined up. However, the diagonal line's angle must change overall as the riser height increases. The stringer angle will change since there is more distance between floors, but the same run.

The risers are all stretching, it is the relationship from tread to tread that is not changing.

I have been thinking about this one for a little while and have not come up with a solution. Maybe someone has already done it, and will share.

Yes thats exactly my problem. Thanks for trying to help

Unfortunately you can't use a variable distance with an array, so although you are getting the individual risers to stretch, the base point for those risers is set by the fixed array distance. You could do what you are trying with a fixed number of risers, but that sort of defeats the idea, and if it where only for 2 or 3 variations then visibility states could help it work, for more than that the work involved would be ridiculous. LISP might offer an easier method.