[Bad print quality]

I am having some issues with getting good print quality on my prints. I recently printed a scaled up low poly pikachu and was disaapointed with the surface quality. It has random verticle lines on it as well as other issues.

I have also had problems with retraction and outer wall appearance. I have attached some photos so if youh know what this is or how I cna fix it then any help would be appreciated. 

[Unknown verticle lines on prints]

Hi all, 

I'm using the latest version of cura on my geeetech a10m. I'm having some surface quality issues. I've attached a photo from a scaled up low poly pikachu and as you can see there is a line underneath the right paw. It has also occurred on both ears. I think that this may be cause by some sort of retraction setting but i am not sure what. The tail also suffers from some weird artifacts. 

I have also recently printed a scaled up burj Khalifa and I am having a very similar issue with that. As well as the strange lines I am also seeing that layers that aren't at the top have lots of holes in them and the lines are not connecting properly. 

My setting for retraction are currently 4.5mm at 70mm/s which seems to be fine with stringing. Both models were printed at 0.15mm layer heights at 60mm/s. I have enabled coasting at 90% speed. 

Any help would be much appreciated. Thank you.