Building tool question

I was curious about the last two building tools the tree and grass.
I tried to find some information about it but I couldn't find anything in the help section.

Linden trees are specially constructed to only take up one prim each. You can make your own by intersecting two or three alpha textures of trees and use the opengl bug to make them look 3 dimensional.

By grass I assume the texture used on the ground? You cannot do anything about that on the mainland - it si set in concrete! (just a figure of speech), while on private islands the sim owner can alter them for up to four height ranges ( iThink separately on sim quarters, but not sure about that)

Actually they are tall grass and short grass, I believe. You just use create and select either one of the tools and rez the grass on the ground. It will "plant" the grass in a 10 m area. You can use the edit tool to move the grass.

A nice feature is that the grass will follow the contour of the land that it is planted on.

You can experiment by playing with it.

opengl bug?
what is this that you speak of?

thank you.

Sorry, not familiar with this grass.

The opengl bug involves uncertainty as to which alpha surface to render when two are close to each other. A problem in building but an advantage with trees as it makes them look more 3d.

I asked because I used the tree and grass tool over some prims and nothing happen.
I figured I was doing something wrong