Smeargle is not availbale in ORAS
Unfortunately Smeargle cannot be caught in ORAS . The only way to get it is to trade across from XY.
In XY it can be found in :
- Route 7
- Normal-Type Friend Safari
However if you don't have Pokemon Bank or a trusty friend to transfer from XY to ORAS or 2 3DSs . You could always try the GTS or the DB Chat.