Facet dome FACES ARE NOT PLANAR for 3D print

Hello. I have this huge problem with a complex geometry that i want to 3D print... but the problem is from the beggining. 

It's starting from a facet dome and the problem is that faces are not planar. 

I just want an irregular shape for a helmet similar to a facet dome with x faces and a random seed. if you have any suggestions please help cause i need to print this for a contest that's coming soon.

Thank you.