Hello,
are there any built in assets like statik meshes materials textures that are ready to use ? because iam learning c++ and maya at the moment but i wanna focus on skripting first. and i also want to have a level that i can use.
if not, is it possible to import the udk meshes in unity 3d?
It might be possible to do that, although I’m not really familiar with UDK. (NO MAC VERSION :() Perhaps you should go to the Collab section and team up with a learning modeller and then you can work together on a project while learning.
Assuming you’re working on some sort of whitebox you could get away with untextured cubes and have more time to dedicate to programming. Add a few lights and it’s practically a level. 
(this works for me at least, your mileage may vary)
I agree with stringbot. use some of the inbuilt primitives to use as game model proxies as you learn scripting, then as you are doing that look for free 3D models or take the plunge into Blender or another 3D modeling app.
Klink
Get yourself a quick proto pack of art assets if you need them. Honestly, for $20 I’ve never regretted purchasing the Frogames pack.
Don’t forget that the various tutorials offered by Unity on their site come with assets that you can use to further experiment with. Additionally, there are free assets and packages on the Asset Store within Unity. I don’t promise you can put together a really good looking game because of the conflicting art styles of various packages, but you can certainly prototype/experiment with them.
Personally, I like start with basic primitives and a few basic shapes created in Blender when I can’t get away with the built-in primitives. That’s lets you focus on making sure the game works and is fun to play. Then you can add better art later once you have things working. (Don’t forget to test the changes the art makes to ensure colliders make and such.) This generally prevents me from spending time futzing with the art and trying to get it to look “right” when what I’m after is a working prototype in the script.
Get. This. Shit. Seriously.
At that price and with how much rapid prototyping you can get out of it, it’s worth every penny and beyond.