I found this comment in the print3d Makefile on line 18.
#Note: as mentioned in http://wiki.openwrt.org/doc/devel/dependencies, the inotifyd dep will not be checked on installation through opkg
I'm trying to install the Doodle3D packages using OpenWrt's Image Generator and I think the problems I face (print3d does not get started) are related to this.
Any clues?