Ok, to make a spinning skybox like my level, first make a skybox like normal, with the skyzone entity in the box, where you want the centre of rotation to be,  then go into the skyzone propeties. First go into Advanced, and change bStatic to False. Now go into movement and change Physics to PHYS_Rotating, and bFixedrotationdir to True. Now change the rotation rate to however you want the box to rotate, the larger each of the 3 values, the faster the rotation

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