It's great to give a chameleon as much natural sunlight as the area you live in permits. Heat lamps and uvb bulbs mimic the sunlight to an extent, but nothing is as good as the real thing. To allow your chameleon to soak up some natural sunlight you can take him outside for 45 min to 2/3 hours at least 3 times a week and this will help him tremendously. You also don't have to give your cham as much calcium w/ D3 supplement as the sun will provide natural vitamin D. Put him on a plant outside that accomadates his size and he should just chill on it soaking up the sun. That's what my veiled does. Make sure your cham has a spot to go in and out of the shade when he pleases though, because if it's too hot outside he/she can overheat. I keep my cham outside in his cage 24/7 and he loves it, but I do live in Florida so it all depends on the weather where you live.