So this is a pic from my smg file.
all those curves, are hoses.. They are all splines so there is not really any straight section of them. I don't know how the image quality got so messed. when i do a high resolution render, nothing changes or anything.
Yuck. Long-shot guess here--have you turned up image quality in your Document Properties Options? If not, might be worth trying out to see if you get any better results.