Clarifying Geometry Nodes Concepts
Recapping Topics, & Asking For Feedback
With January quickly wrapping up, I thought I'd take this article to do a little recap of our adventures in Geometry Nodes and look ahead at what I'm planning to cover next.
Geometry Nodes is still in its infancy compared to other DCCs that have a much more mature and capable toolkit. Even though it can still pull it's weight, Geometry Nodes still requires a full-focused approach to reach the same heights as other DCCs. It's becoming readily apparent to me that there is still a lot that can be uncovered within Geometry Nodes. At the same time, I'm not entirely sure if it's something that can be easily uncovered and translated into a newsletter format week after week.
This is to say that I'm asking for input. In the next couple of days I'll be sending out a survey to all of my wonderful subscribers about what you've thought about this past month and what you'd like to see us cover next. After all, this publication is a two-way street, and even if the feedback isn't directly offered, I still have ways of figuring out if I'm hitting the mark or not. I love all things 3D, so whether it's diving deep into Geometry Nodes or talking about rendering pipelines, I am more than happy to get my hands dirty if it is an interesting read for y'all at the end of the day.
So stay tuned for that survey email and please make sure to fill it out! Even if you just have a passing interest in MipMap I would greatly appreciate your feedback!
Loops / Zones
Single-handedly, loops were the trickiest topic to write about. It's easy enough to explain what the three loops do in Geometry Nodes, but putting them into practice is a whole other beast. The Repeat Zone is pretty straightforward, and is the most ubiquitous out of the three. The Simulation Zone actually came out before the Repeat Zone, but it has a very niche application that I haven't touched on. With the For Each Element Zone, I was (regrettably) completely out of my depth. I've seen people use them, and I know what their purpose is, but I still can't wrap my head around it. I guess it's just one of the natural boundaries that is going to take a bit more time.
To summarize each zone, they look like this:
- The Repeat Zone is used to repeat the contained nodes over the geometry you give it. Using an Iteration Count as the control, you loop over the geometry however many times and do the exact same set of actions on every iteration.
- The Simulation Zone executes the contained nodes every frame. Everything you want to do has to be contained within the zone since it acts like a box that takes in everything before the zone, re-calculates it for the current frame, and then does anything that comes after the zone once the frame is calculated.
- The For Each Element Zone applies the contained nodes to every ID in a certain element. Remember that an Element is the type of geometry that is being worked one, like a vertex, an edge, a face, or anything else. We can give the zone a Selection field to specify what element of the domain we apply the zone too, along with using the ID of the element to act as a unique seed for any random functions. This zone outputs both the original geometry put into it along with a separate geometry of the results of the zone.
Just using the Repeat Zone within Geometry Nodes will get you 80% of where you want to go, and it's only when you start wanting to bring in other aspects of Blender (like simulations and instancing) that the Simulation Zone and For Each Element Zone are really needed. However, they can both open up their own unique workflows that can lead into even more possibilities if you dig a little deeper.
Attributes & Fields
Fields are a simple-yet-complex part of Geometry Nodes. If you mix up your socket connections you can find yourself losing hours only to find out that you just had the wrong Field plugged into something. I also feel that I might not have been very clear with how Fields really work.
It's easy to think of Fields like you do other nodes. Place one down and it has it's spot in the order. However, Fields are just references to values at any given point. They reference Attributes on their geometry that you can't touch or interact with otherwise. Instead of thinking of them as Attributes, maybe it's better to think of them as Absolutes, values that you can only ever look at and call upon but can't overwrite or change in a direct way.
There are some nodes that allow you to directly change these Absolute Attributes, but they aren't done overtly. The ID Field node references the ID of a given element in a specific domain, for example, and we can't change the ID of that element unless we add new geometry and set our first geometry to be added after other geometry. That way it gets shifted down the ID list on the Spreadsheet, but it technically still remains in the same order as it was when it wasn't joined together.
In the same vein, any Attribute that you create can best be thought of as Variables that you can set, change, reference, and overwrite as needed. The only difference is that they exist on specific element domains, meaning you have to keep track of where the Attributes are stored.
Future Plans
To wind down this article, I’ll give a little bit of a roadmap for the next month. February is going to continue investigating Geometry Nodes, looking at some more advanced concepts and methods. Currently, MipMap’s schedule for the next month looks like this:
February 3rd: How To Generate Landscapes With Procedural Noise
February 6th: Wireframe 005
February 13th: Making Geometry Node Tools
February 17th: How To Procedurally UV Unwrap Geo Node Meshes
February 20th: Adding Animation To Geometry Nodes
February 27th: Clarifying Concepts From Earlier Articles
March 3rd: How To Naturally Scatter Assets
Beyond February however, is up in the air. This is where I circle back to the survey, and gratiously ask for your feedback. Should I continue making articles on Geometry Nodes? Should I move onto making articles for other aspects of Blender? For other DCCs? Do you even enjoy these kinds of articles?
There’s a lot of questions that I’d like input on. But for the time being, we are full steam ahead on Geometry Nodes. Support MipMap and receive the next How-To on Monday, and stay tuned for next week with our monthly update with Wireframe 005!
If you enjoyed this article, please like and sign up for a free subscription to MipMap! Or, if you didn’t enjoy then leave a comment to let me know what I can do better for the future. Either way, thank you for reading MipMap!
- Adam