I'm aware of that option and this will be implemented, but still there is something wrong with the provided data to the binary ttf compiler...

Thanks Jens its seems to be a fontTools issue :) http://sourceforge.net/p/fonttools/code/ci/master/tree/Lib/fontTools/ttLib/tables/_g_l_y_f.py#l549 it seems to recalculate the bounds from all points instead of analysing the bounds of the contour (this will be fixed in the next version...

Thanks, that did it! :)

Did some tests and this issue is already solved. It will be in the next update.

the ttf "path": RF UFO > internal ttf compiler on top of ufo2fdk > glyph data .ttf > fdk for some tables > .ttf

RoboFont will check the splines and convert them to two off curves splines in the next version. (in version 1.1 it doesn't check WOFF files, but it should :) Although WOFF files with PS outlines should work fine. Bonus answer: no ;)