Quoting Zhichu Chen
Hi Aditya,
Actually, they should have the same boundingbox, the first MPdrawing environment draws a line from (0,0) to (2cm,2cm) and the sequence MPdrawing environments just add two lines that are in the previous boundingbox.
I know what's happening now. \definesymbol doesn't define a symbol from \getMPdrawing at once.
Yes, \definesymbol[a][b] is roughly equal to \def\a{b}, for example \starttext \def\something{aa} \definesymbol[aa][\something] \symbol[aa] \def\something{bb} \symbol[aa] \stoptext This is what is also happening in your case. You need to go back to the definebuffer and processbuffer as suggested in metafun manual. I do not know if it makes sense to have a \edef version of definesymbol. In any case, getting expansion to work with \getMPdrawing is going to be difficult. Aditya