I'm just curious, I've played guitar for a year and a half, both acoustic and electric and I was wondering how hard it would be to get a bass and start learning songs and stuff. I understand that I would need to learn techniques (slap!) and all that, but what has it been like for you multi-talented people?
Actually, having the knowledge of a year or more on the guitar, you at least have a place to start. Basslines have a tendency to move around a little more, but changing any instrument will only broaden your horizons, expand your knowledge, and challenge you when you are in a rut somewhere else. One thing that helps in going from guitar to bass is the tab works in the same way.
it won't be hard to learn new stuff and songs on bass depending on the style. if it was mainly just simple rock then it won't be hard. if it's something featuring the slap style or something like that then it may get a while to get used to (i still haven't got popping/slapping down).

it's easy to learn any instrument. what's hard is mastering it. so don't worry about it so much. you said you played for 1+1/2 year so it won't be hard to learn. if you're going to learning the simple finger plucking way, then i suggest you get used to plucking and alternating with your index, middle, and ring fingers. mainly index and middle. i use my ring finger when there are things like galloping lines or triplets.

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As has been previously said, you'll find it easier than the average beginner, but it don't expect it come to straight to you. The heavy strings and different string spacing may prove tricky to get a grip off, but once you do, you'll be fine.
One thing though, finger picking on guitar is a lot different to finger picking on bass, on guitar your using your thumb for the first three strings and fingers the other three. On bass you'll be using usually two fingers at all times.

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I played guitar for two years and switched to bass, picked the basic two finger plucking up in a week and the spacing isnt that difficult to get used to. Be prepared to have to form tough calouses on the picking hand though its that uncomfortable process again for about a week or two, bit annoying if you thought you would never have to get them again. xD

Personally having switched though I find I enjoy bass much more than guitar.
I played the guitar for over six years, including playing in several bands and doing a lot of gigs, before picking up the bass, and had little trouble getting the basic technique down. I also immediately started playing in a band where the guitarist, drummer and violinist have all studied their respective instruments in music schools (whereas I'm completely self-taught), and was able to keep up without difficulty. Playing in bands also gave me a good sense of rhythm, which I think is one of the essential skills for any bass player.

So I'd definately encourage you to give it a try - you've got a nice head start on the average beginner, like astrocreep71 said a few posts above. The string gauge and spacing as well as scale length will probably be the most difficult thing to get used to at first.