Solved custom body kit problem

I'm started creating custom body kit for sunburst. I edited right fender flare. Is any easy way to make left mirror fender flare? i tried to copy and make mirror, but is not working in game.

 

Makes sure you apply rotation/scale/location before exporting.

Select all objects with 'A'
Press 'CTRL+A', select 'Rotation and Scale', and do the same with 'Location'

 

Add the mirror modifier in blender and then click "apply", alternatively check the "apply modifiers" box that appears when exporting the .dae. If you want them to be separate (as the fenders on the sunburst are seperate) then after you apply the mirror, go into edit mode, select one of the fenders, and hit ctrl+p to separate it. Also make sure the objects origin(the orange dot that lights up when you select a mesh) is at a location of 0,0,0 just for the sake of making everything easier

 

Thanks you

Thanks you too, but not ctrl+p, just only p to separate it