Error Mess: Cannot DEL transformation ??

[Dave Jochum]

5 minutes before a client is due in my office I find what I think is a duplicate slab in the section window. I delete it, and without saving (so I could just undo if necessary), view the model in 3D to make sure I didn't just trash something I wanted. (I was unsure, because in plan, selecting all did not show a duped slab.) As the 3D window script is running I get about 20 error messages like the one attached, but with different line numbers referenced. I went to undo, but it was greyed out. Just my luck I guess that an autosave had just taken place. It obviously refers to casement windows, none of which I touched in deleting the slab. Can a GDL guru out there tell me what this means and how to fix it?

TIA

[Anonymous]

Daniel wrote:

Matthew wrote:
Of course it's possible, just VERY unlikely. Transformations are rarely (if ever) driven by user parameters.

Matthew

Transformations are often conditional and driven by user parameters.
For instance the number of times the origin is moved to insert a glazing bar (muntin) in a window is determined by a loop that is driven by the grid size in the user parameters. Good scripting needs to also make the DEL lines conditional in the same way, to take the right number of steps back.

Daniel,

You are right, bad code can lead to this problem (and many others). I was thinking of PROPERLY coded parts. The transformation stack always needs to be handled to accommodate whatever variables may occur (user parameters or otherwise) as in:

FOR i = 1 TO n
add a, b, c
! do something
NEXT i
del n-1

The reason I did not suspect bad code was that the library part did not produce any errors for me or Link using the same settings that generated the errors for Dave.