Hey !
@ Joanne :
That tutorial is no more available, but if you have questions, feel free to open an other thread, e.g. concerning the roof texturing, which btw. can be done quite easily.
Note : More new official CityEngine training materials are currently being produced.
@ Ramli :
I've made a simple little GUI some time ago, but I currently don't remember which way I did it. Please just open a new thread in the CityEngine Python Forum. I'll try to find the example, so I can post it there.
The GUI in CityEngine itself can sadly not be changed at the moment, but we've had this request before, so this may be something which will be possible sometime in future.
matt