My 2 1/2 year old son wont use the potty!?

I have a girl thats 2 1/2 that was just like your boy is. I know boys and girls are different but i read an article online that i tried and it worked amazing. Its kind of crazy but it worked for us. I took off her diaper and just let her run around naked she went on the floor twice and then after she noticed what she did she started sitting on the potty all by herself. Now I have her in underwear. But i tried putting her in underwear to start off with but she just thought of it as a diaper and peed in it. THen i made a chart so she put stickers on it which worked great. I know its a little out there but i wanted to try anything to get her potty trained since i have an 18 month old boy as well. One kid out of diapers is great.