I want to create a scene have lotta trees.Could you introduce some demos to me?
thanks
“Penetratable forests” is an incredibly difficult problem in real-time 3D.
There are session on this kind of stuff at SIGGRAPH and GDC.
Here are a couple of none gaming links I just grabbed from Goole using “Virtual Forest” that give a bit of the complexity
http://www.innovativegis.com/products/vforest/contents/vf_examples.htm
http://www.innovativegis.com/products/vforest/contents/vfoverpaper.htm
Good pruning!
if the trees a far away and don’t need to be seen from too near, the billboard behavior could be your solution.
The billboard behavior automatically orient the (textured) face to be facing the viewer’s eye.
it’s explained in sun’s java3d tutorial (chapter 4 & 5)
and here, a piece of the text:
“The classic example application of the billboard behavior is to represent trees as 2D textures. Of course, if the textures are statically oriented, as the viewer moves, the 2D nature of the textures is revealed. However, if the trees reorient themselves such that they are always viewed parallel to their surface normal, they appear as 3D objects. This is especially true if the trees are in the background of a scene or viewed at a distance.”
hoping it helps…
The other very common variant on this effect is using two flat 2d shapes crossed with a tree texture on both of them. This is used all over the place for plants that look ok from a distance if a bit manky close up ( Operation Flashpoint and Zelda 64 both do this, among many many others.)
and if you wanna see them in “real 3d” when you approach, you should use a LOD behavior.
The more you approach the tree, the better it is modeled.