Need help with blender

So guys I'm working on a race Game and have modeled few cars we are going to use only materials as its a racing game so I separated each objects by materials but the programmer isn't happy with it cause more objects makes it difficult for optimisation

So can I make all these objects into one?
http://prntscr.com/hfbexu


If anyone knows solution for it please tell me.

 

I hope I understand your question correctly.

Okay: One thing you could probably do....
Is make all of the wheels, all share the same material.
And probably combining all of the wheel textures, into a single texture atlas
might help?

If I did not understand your question, could you provide us with more info?

 

In Blender, you should be able to select all of those separate objects and use Ctrl + J to "join" them into one piece.

Note that if you're making a car, you may need at 4 objects to be kept separate from each other for the wheels so they can rotate independently in animations. But you can join all the parts for each wheel since they'll probably animate together as one unit.

 

You use several materials in one object.
1. Add material
2. Choose faces and click assign