any progress on this front?
Sort of - I think that for realism we really do need some large trees, for forest areas, but upon examining the model inside Blender it looks like it might be less messy for me to create my own models of tree parts rather than try to break up these existing ones into sections by height, for the different map levels.
The pine trees actually appear to have a rather simple design - the branch/leaf texture is repeated and split into four quarters of a 2D plane, and those four sections of the plane are bent downward for each branch.
@H-Hour: Can you create a leaf/branch texture as shown in the attached pic for various types of trees? For new textures the branches would have to go straight across the horizontal axis, like the existing one shown.
@Mattn: If I make sections for spanning multiple map height levels, wouldn't it be easy to have each level/model rotated along the vertical axis by a random amount during map creation? This would randomize the trees, so they don't look like clones, and allow creation of a more realistic-looking forest, because the branches would be rotated to be in different places for each tree.
If you'd like, I could also attach TAGs (since models used for maps support them now) to the bottom-most section of each tree, and all the model parts that make up sections of the tree's trunk above it could be attached, allowing the tree to bend or sway in weather. The only question I have about such a setup is whether or not the upper parts can still be switched visible/invisible, for when the player is viewing things at a lower vertical map level (and wouldn't want to see the upper parts of each tree).