basically I did the following, if I remember correctly:
Add Bezier curves, grouping them when finished, making sure to taper them with alt-s/shift-s (sorry can’t remember which)
Run the script
Select the curve and click “automatic update”, this should create the tree mesh from the curves.
Its then just a matter of messing with the settings, mind you, I never managed to get the leaves working.
Cheers Burns but I already got this far - it’s what steps to follow after the initial bezier curve trunk setup that I wasn’t having much luck with.
I’ve since played with it a bit more. Looks like I wasn’t drawing enough curve branches for the additional options to do anything.
I’m getting sporadic results with several of the features (purely because I’m not totally sure how they work) but especially the leaves. They appear but are all over the place with a lot not necessarily attached to branches. There’s indication in the Peach blog tree entrythat some sort of bounding mesh needs to be used - had a few goes at playing around with this but didn’t get anywhere.
Tried using similar settings shown in some of Campbell’s screenshots and a mutant monster with little relation to a tree emerged - a good candidate for why a quick video demo would be really handy!
I got as far as you with the leaves, they ended up going all over the place.
Ok, I know i’m bumping, but i played around a bit with this and thought i’d show what i’ve got. I basically only have three curves, the rest are “twigs”, but i think i could have gotten better results using more curves. Ok for a test though, i think you could do quite a lot with this.
hey this looks great, how did you get the leaves working?
Well, first off you need to have twigs.
Secondly, I needed a leaf object specified, in order to see them in a render
Thirdly, the center of the leaf object must be at the center of the tree.
Finally I moved the center of the leaf to its stem, as when it was in the middle the leaves were pierced on the twigs.
Did that help you?
yeh that helped alot but I can’t get more density for the leaves like your render, any ideas?
Well, I think you simply need more twigs. I’m not quite sure, and i haven’t currently got the time to check for sure, but it seemed to me like i got more twigs when i duplicated my bounding object while in edit mode.
http://wiki.blender.org/index.php/Scripts/Manual/Wizards/TreeFromCurves
Found this, maybe someone who knows how to use this script can finish it.
A great render by the way.
Great news - Campbell added a tutorial video to the TreeFromCurves wiki entry. Thanks very much Campbell - very much appreciated. There’s nothing quite like a video tutorial to set you on the right path (I was missing one or two vital steps for getting decent results).
See the video and some screenshots here:
http://wiki.blender.org/index.php/Scripts/Manual/Wizards/TreeFromCurves
Alrighty, I’ve been trying to get this to work for a bit now and every time I go to press Generate from Selection, a message pops up that says “Python Script Error: Check Console”
I believe I’ve got Python 2.5 for mac installed in my applications folder already. Is there something more I should do? Find some way to point Blender in that direction?
I don’t get how the peach guys use these trees…they are high-poly!
Where do I download this magic trick?!
The used the mesh produced by the script and then refined it with Multires and some scuptling. That produced higher poly meshes plus they used some normal maps produced with the sculpts.
Well at least I guess they did it that way. 
This looks purty neat 
i’m alittle stuck here. i can’t figure out how he gets the mesh onto a different layer, and how he gets the twigs to show up. what is a bounding mesh?
EDIT: Nevermind. i got it figured out.
The used the mesh produced by the script and then refined it with Multires and some scuptling. That produced higher poly meshes plus they used some normal maps produced with the sculpts.
Well at least I guess they did it that way.
Cnikiel: actually not.
Andy modelled by hand the trunks and the roots the more lowpoly he could, then Cambo made the branches (matching the curves to the modelled trunk) with the leaves by the script, then I uvmapped all the trunks and the resulting branches, in some case I joined the branches to the trunk, in others not, then I sculpted the bark on planes, baked the normals, tiled the result in the Gimp and applied them to the uvs of the models.
Starting from the normals, I painted also color, spec and diffuse maps. Very easy.
Hey I looked at the video but I can’t scale on vertex. Can someone help?
blenderman345, the scaling of the bezier vertex is done with ALT-S. This will make the trunk/branches thinner or fatter.