A Few Questions About Unity (I'm a beginner)

What is the pros and cons of Unity?
How to solve "This following disk images couldn't be opened error"?
And is physics engine good in Unity?

 

Unity uses PhysX for physics. Pretty much the same as everyone else.

 

Have used Unity 4.x - Keep an eye out for version 5 (or you can buy it now).

Pros:
Easy to pick up and play with if you have some experience programming, if not start in the rather good learning section above.
Gives access to Directcompute on the PC to unlock the power of your GPU.
Uses the C# programming language with it's library of built in features.
Allows you to quickly and easily throw together prototypes.
An amazing collection of Assets on the asset store to get you up and running faster.
New UI toolkit built in.

Cons:
Has limitations, is mainly single threaded, is aimed at mobile games platforms so does not allow you to use all of the CPU/GPU on modern high end PC's.
Not all of the features are available in the free version e.g. Profiler / Shadows.
Uses Mono so can be slower than native game engines.
Does not have all of the dream features you will need out of the box, expect to spend some money in the asset store.

Note: the PhysX has been greatly improved in 5, 4's physics is renowned for having a few problems especially with vehicle physics and slowing down when things get complex.

Not sure about your error, try googling with Unity3d as a prefix.

 

Not sure where you got that idea from.

 

Unless your scripts are performing heavy calculations on a frequent basis you won't really see a difference. There is a way around this limitation through the use of native code libraries.

 

GC Hiccups!

 

Good point I think that is because I have not seen as many big PC games made with Unity as other engines.

 

Poorly written code is going to perform poorly regardless of the language.

Blame Unity for their crazy mindset of removing the splash screen when upgrading to Pro.

 

Exactly whoever wrote that garbage collector needs to think about us poor game developers who can't spare any milliseconds just to clear up a few kilobytes at some random frame a few seconds into a good bit of our game.

 

I've never understood why developers are not given the ability to disable/enable garbage collection. I'd love to be able to disable it and only run a pass during load screens or similar periods where frame rate isn't important.