Fir Tree Generator
Overview
This is a procedural fir tree generator made with Geometry Nodes, with a bunch of parameters that allow you to customize the appearance of the tree and create endless random variations. It works well both with Cycles and EEVEE. To use it, you can append the tree blend file to your project, or add the folder in Blender Preferences>File Paths>Asset Libraries, in order to have the tree accessible from your Asset Browser.
You can use one of the 3 pre-made tree shapes, or select tree shape number 4 if you want to fully customize the tree using the orange-colored curves inside the Geometry Nodes editor.
This Geometry Nodes setup is applied to a curve, so you can delete its vertices and draw your own curve, and the tree will follow its shape.
If you're using Cycles, I recommend setting the Transparent Max Bounces in the Render Properties at 24.
Customization
I've added descriptions to the parameters that are not self-explanatory, so you can hover over them to check that. Here's a quick overview of the basic customization:
If you want further customization, you can edit the orange-colored curves inside the Geometry Nodes editor (if not, you can skip the rest of this section completely). These are the features that you can edit there:
- Branch length in relation to height. Use this to establish the overall shape of the tree.
- Branch rotation in relation to height. This refers to the vertical orientation of the branches.
- Twig density in relation to height.
- Less twigs on center in relation to height. It looks good when there's some space between the trunk and the point of the branch from which twigs start growing. This curve lets you edit how much of this effect you have on each branch, depending on how high they are on the tree.
You'll see that for each one of these features, there are 4 different curves arranged vertically. The first 3 curves correspond to the pre-made tree shapes 1 to 3, and the 4th curve is a blank curve that corresponds to tree shape number 4.
You can select and edit tree shape number 4 if you want to create your custom tree from a blank starting point, or alternatively, you can select and modify any of the other pre-made shapes if you just want to make some changes to any of them. Whatever suits you better!
Performance
This tree has been made with performance in mind, so all the various resolutions are customizable. The default tree is under 10K vertices and looks alright for mid-distance shots. You can easily increase the resolution of the trunk, branches and flare for close-up shots, and decrease it (or even disable the branches) for distant shots.
Another trick to increase performance that looks alright for trees in the distance is lowering the twig amount and increasing the twig size to compensate for that.
Adjusting all these parameters allows for big forest scenes like the one in the sample video.
Wind Animation
The tree comes with a wind animation that runs in real time in the viewport (at least on my mid/high-end laptop). It has options for generic wind as well as directional wind.
Unfortunately, if you use multiple instanced trees with random rotation, the directional wind will follow the rotation of each instance instead of a general scene wind direction. I have not found a way to get around this; if you do, let me know!
Licensing
You can use this for personal and commercial projects without any limitation, no crediting required. Only thing you cannot do is sell the generator, or any trees made with it, as a product.
Let me know if you have any doubts and I'll try to help!
PS: I made this following various tutorials, without knowing what I was doing at first, and having a mid level understanding at the end 😁 So you can expect things that don't make much sense or could be done better if you take a close look at the Geometry Nodes setup. If you make any improvements, let me know; I'm interested!
Artwork used as reference for the video sample landscape: https://www.artstation.com/artwork/8BaAbq
Terrain made with Hesiod, an Open Source node-based terrain generation software: https://github.com/otto-link/Hesiod
Leaf texture: https://ambientcg.com/view?id=LeafSet019
Bark texture: https://ambientcg.com/view?id=Bark001