The private pilot reported that during cruise flight at an altitude of about 800 ft above ground level, the engine lost power. Despite his attempt, he could not restart the engine and initiated a landing in the open desert. During the landing roll, the aircraft impacted a large boulder. The pilot stated that the examination of the trike after the accident revealed that he had ran out of gas. The pilot added that the trike was not equipped with a fuel quantity gauge, and that the only way to verify the fuel level was visually looking into the fuel tank. Additionally, he thought he had a full tank of gas prior to takeoff.The trike sustained substantial damage to the forward upright wing support tubes. The pilot reported that there were no preaccident mechanical failures or malfunctions with the trike that would have precluded normal operation.