Ivy Generator in Blender 3D
Blender 3d tutorial
The Ivy Generator is an addon in Blender 3D that allows you to easily create Ivy that will crawl across the object of your choosing. This is a very simple effect that can quickly bring some life to your scene. In this Blender tutorial, I will go over how to properly generate ivy in your scene and then talk about how to add some materials and textures to create the render you see here!
Start off by removing the default cube. You can use any object you like for this tutorial, but I will be using Suzanne (Add->Mesh->Monkey). There isn't a specific reason to doing so other than to have an object that is a bit more interesting than the cube.
Once you have your object ready, we need to make sure that we have the Ivy Generator addon activated. Even though the IvyGen addon is already packaged with Blender, we still have to make sure it is turned on so we can use it. You can do this by going to the user preferences (Ctrl->Alt->U) and selecting the Addons tab. Type in IvyGen into the search box and make sure that the box is checked.
Generating the Ivy
Next we have to decide where the ivy is going to start from. This is determined by the position of the cursor. To do this, select your object and go into Edit Mode (Tab). Select a vertex where you want your Ivy to start from. As you can see here, I picked a vertex on the chin of the monkey.
With a vertex selected, you can snap the cursor to that point by pressing Ctrl-S and selecting Cursor to Selected in the popup. Once you've done that, hit Tab again to go back into Object mode.
Now make sure your object is still selected. This is important, because if you don't select the correct object, the generator will not grow on the correct object. To generate the ivy, you can find it at Add->Curve->Add Ivy to Mesh. Blender should take a moment to add the ivy onto your object and you should see a large amount of settings appear at the bottom of the tools panel (T Key).
Changing the Overall Shape
I start by determining the overall shape of my ivy plant with the Size settings and the Weight settings. Keep in mind that depending on your object, you may experience much different growth than I get here.
In the size settings panel, I first change the Max Ivy Length and the Ivy Size. These change the overall size of the ivy and the length of each branch segment. If you find that the ivy will not grow larger no matter how high you set these, then increase the Max Float Length and Max Adhesion Length. These limit how far your ivy can float off of and stick to the surface of your mesh.
The weight settings section includes settings that control how prone the ivy is to grow in certain directions. The closer Primary is set to 1, the straighter your ivy will grow, Random gives the ivy random changes in direction, a higher gravity will make the ivy more likely to hang down, and Adhesion will make the ivy stick to your object more.
Fortunately, all of the settings have really good descriptions when you hover over them, so if you forget you can find out what they do very quickly. And as always, I encourage you to play around with the settings yourself so you get an idea of how the settings works. There's no better way to learn then by doing! In any case, you can see why my settings are in the image above.
Branches and Leaves
After you've set the overall shape of your ivy, now we can get more detailed with the Branch Settings and the Leaf settings. These are fairly self explanatory, but the Branching and Leaf probability change how many branches or leaves are generated and the Branch Size and Leaf Size will adjust the thickness of the branches and the size of the leaves.
As before, you can see my settings in the image above, but I highly recommend altering these settings to fit your personal preferences. There's no right or wrong here!
Finally, you can play with the Random Seed setting and change it to random values until you find something you really like. Sometimes the differences can be pretty drastic, so don't hesitate to try changing to seed if you don't quite like your ivy.
Now that we have our ivy all set up, we can add materials. You may have already noticed, but if you look at the generated mesh, you will see that the Ivy Generator creates two objects, the branches (named 'IVY_curve') and the leaves ('IvyLeaf'). This makes it easy to add materials to each one.
I am going to start with the branches, so select the branches object. Then you want to use the Cycles renderer and change the window layout of Blender to Compositing. In the node editor, add a new material and name it 'Branches'. It's always a good habit to name your materials!
To keep things simple, I am just going to mix together a Diffuse (Add->Shader->Diffuse) and a Glossy (Add->Shader->Glossy) Shader, as shown in the image above. I chose a brown color (RGB: .200, .140, .80) for the Diffuse shader and left the glossy shader white.
Leaf Color and Specularity
The leaves are a bit more complex than the branches as we need to get leaf textures. You can use your own textures, but I will be using ivy textures I found at a site about an ivy generator for the Bryce 3D software.
Back in Blender, with the leaf object selected, add a new material and rename it 'Leaves'. Then add four Image nodes (Add->Texture->Image). Then load 'efeu0.jpg' (Leaf Color), 'efeu0_bump.jpg' (Leaf Bump), 'efeu0_trans.jpg' (Leaf Transparency), and 'efeu0_rough.jpg' (Leaf Specularity) into the nodes. I also changed the label setting text in the Node section of the sidebar (N) so I could see what each of these nodes are more easily.
First, take the color output of the Leaf Color node and plug it into the existing Diffuse color input. Then add a Glossy Shader (Add->Shader->Glossy) and a Mix Shader Node (Add->Shader->Mix). Plug the output of the Diffuse shader into the first Mix Node Shader input and the Glossy shader into the second. Finally, plug the Leaf Specularity color output into the Fac input of the Mix Shader node.
Leaf Bump and Transparency
Next, add a Bump node (Add->Vector->Bump) and plug its output into the Normal inputs of the Diffuse and Glossy Shader nodes. Then plug the color output of the Leaf Bump node into the Height input of the Bump node. Finally, set the Strength setting of the Bump node to somewhere around 0.100.
For the Transparency, add a Transparent shader (Add->Shader->Transparent) and a Mix Shader (Add->Shader->Mix Shader). Plug the color output of the Leaf Transparency node into the Fac input of the new Mix Shader. Plug the Transparent BSDF output into the first Shader input of the new Mix Shader. Plug the output of the previous Mix Shader into the second Shader input.
Finally, plug the output of the new Mix shader into the Surface input of the Material Output shader. Once you have done that, your leaf material should be complete!
Now that you have your ivy is complete, lets take a final render! Be sure to set up some lighting and if you want to add any material to your monkey or whichever object you used, go ahead and do that as well, then take your final render (F12)!
And that is the end of this tutorial! If you have any suggestions, questions, or comments, please don't hesitate to let me hear 'em!
No single tutorial will cover everything, so if you want to dig deeper, here are some resources for you to check out. If you have other resources you think I should add to this list, feel free to let me know!