Yes! Thomas! This is what I want

Your plugin save my time a lot. Thank you very much.

Thank you, mitcorb. I found what I seek now, it's smart drop (by a4chitect).
But it's still not correct to my need. My problem is show in the image below.

All of these boxes are group and when I use smart drop, they will put perpendicular to the surface.
I just want it straight drop and touch surface only.

Hello,

I'm finding plugin which can put component or group onto the terrain.
Like put many trees onto the hill in the same time.

I think I used to try this plugin but I can't remember the name of this plugin.
Please tell me if you know the name.

Thank you.

I use this plugin to my model, It's help to improve atmosphere a lot.

Thank you very much.

<model link>
http://sketchup.google.com/3dwarehouse/details?mid=5e3202cae2da28223fc4dc5809e00c5c&prevstart=0