A lot of people have problems modeling plants. I found my own way and because it's an easy and fast one which gives a pretty
good result, I want to share this method with you. I am not going to make very photorealistic plants here, if you are going to do this, you should use references from a biology book, or elsewhere.
1. The Leaves
First of all, we need to draw the leaf's shape in a 2d programme. There is no need to have a mega powerfull programme, it could also be possible to use MS Paint. Well, I will use the freeware programme "GIMP", because it's very powerful, and easy to use.
Make a new file. I use the size 256 in the width, and 400 in the height.
Now simply draw a leaf. Use very thin lines for the outer shape, and a bit thicker for the mid-line.
It's important that you take your time, we will not only use it as a reference, it will still be used after modelling.
Now you we will make it a bit smoother. If your painting programme supports smoothing, smooth it twice, if not, simply download the picture.
Now let's get to the interesting part.
Open your 3D programme (I'm using 3DSMAX 5.1 here), and use your leaf as a background picture in the front view.
Under "Views"; "Viewport Background" make sure you have selected the options like here (red marked).
Now place a plane with one lenght segment, and 2 width segments on the reference, and right click on it, and under properties select "See-Through", you also need to make the viewport show "Smooth+Highlights" and "Edged Faces". Convert it to "Editable Poly" and make it fit to the reference, the mid-line has to be on the references mid-line, of course:
Now extrude the two lower edged downwards, and make them fit, again.
Keep doing it, until the whole leaf is finished.
Now open the Material Editor and create a new material, call it "Leaf_01".
In the "Shader Basic Parameters" select "2-Sided", and "Blinn".
In the "Blinn Basic Parameters" unlink the "Ambient" from the "Diffuse" color, and make the ambient color black. Also make the "Opacity" Value "90".
Now go to the "Maps" dialog, and chose "Bump", use the same picture for the bump, as you used for reference, and in the "Output" dialog choose "Invert". That's important, or the bump map will work in the wrong direction!
Now apply the material to the plant, and give it a "UVW Map" modifier.
Now select the "UVW Map's" gizmo, press F-12 and set all values to "0":
Now resize the gizmo, that it fits to the reference pic.
Make a testrender, it should look similar to this.
Not really good, yet, but that will change later.
You can now remove the background.
Convert it to editable poly again, and add a "FFD 4x4x4" Modifier, and move the very left, and right points backwards.
Now select the lower points, and move them backwards, as well.
Only add a "Mesh Smooth" modifier with Iterations "1" in the render values, and the modeling part is done.
It only needs some color, and the leaf will be finished.
Open the material editor, and in the "Diffuse" slot choose the "Mix" map.
In the "Color #1" slot use a "Noise Map", with similar options to these.
Get back to the "Mix Map" dialog, and copy the noise map into the "Color #2" channel:
Go to the second noise map, and make small changes to the color.
Now add the same map you used as the bump in the "Mix Amount" channel.
Get back to the "Maps" Dialog, and lower the "Bump Amount" to something around 10.