If you are a Blender user then you are probably aware of Geometry Nodes introduced in the past year. Unless you live under a digital rock it’s difficult to miss this addition anytime you look for a Blender-related tutorial or if Blender videos are something you frequent. YouTube has a plethora of videos on the subject from practical to abstract art.
Nodes have been around for a long time as used in the material aspect of Blender and particle systems have used nodes for years. Apps like Houdini can do just about anything with nodes. While many users have embraced them, other users find them confusing and fussy. “How am I supposed to know what I use in a node branch or tree?” is a common question for those new to the concept.
Well, that’s the beauty of nodes. The discovery of what you can use in a node tree and how you place them within that node tree for the final result. It’s like programming… you visualize what you want to get accomplished. Chart out a way to get there and consider what tools you will use within the node tree to get your desired result.
Let’s take a look at node tree basics beginning with a new node attached to a simple geometry plane. The image below shows two new nodes, Group Input and Group Output that will define our geometry. Anything placed between those two nodes will have a direct effect on the final mesh. These Group Nodes can define single objects or groups as we will use in this example.
Our task to populate a plane with rocks and flowers using only one rock and one flower object. The node tree will multiply and place these objects, so we need a few other nodes to get the job done. In particular, we will need a Distribute on Faces node to place the objects on the face of the plane. Then we will use an Object node to pick (define) the object we want on the plane. Well also need an instancing node (Instance on Points) to place instances of those objects.
The following image shows the nodes added to the node tree and explains what each node does in simplified terms. The Distribute on Points node also controls the density of the objects and type of placement. You can run up the object density to high levels as they are only instances of the objects.
This takes care of the rocks, so we need to copy the three nodes at the bottom of the tree and place them either to the side or up above the existing tree to keeps things simple. Reusing nodes is a time saver. We then select the Flowers instead of the Rocks with the Object node.
We also add a simple Set Position node to the flower group, so it won’t be on top of the copied rock nodes. Rocks on top of flowers is not a good look. Maybe the other way around would work but the Position node lets us move the Flowers around. There are other nodes and ways of accomplishing the position of objects that are more complicated and more easily controlled than this simple example but this can you started.
As you can see in the final result below, we used one rock and one flower object with nodes to populate the entire plane. The bonus is… select the plane and go to edit mode then scale the plane up and down and you will notice it spawns more objects the larger you make the plane and vice-versa. Very handy for creating game geometry, terrains and other objects.
It’s much easier to populate a plane using nodes than it is with manual placement of each rock and flower. You can also add nodes for a more random rotation and position of objects. This example only uses two objects, but you can duplicate and paste nodes again and again to add as many objects as you need to the target geometry whether it be terrain, plane or prop.
Geometry nodes are not only worth the time to learn, but they are also fun to create and experiment with using other nodes to tweak the final results. The best part is that nodes are a non-destructible method in that you can go back to a node time and again to change its values.
M.D. McCallum, aka WarLord, is an international award-winning commercial graphics artist, 3D animator, published author, project director, and webmaster with a freelance career that spans over 20 years. Now retired, M.D. is currently working part-time on writing and select character development projects. You can learn more about MD on his website.