Select What You Want in Geometry Nodes - Blender Tutorial

In today's lesson we're going to be diving deep into selections. Learning this well will be transformative to your procedural workflows, not just in Geometry Nodes but across all procedural systems.

Correction: Accumulate Field node's "Total" output does not tell you how many elements have been counted, it returns the sum total of whatever values it has counted up. When the Value is 1 as in mine, that means it added 1 per element which is why I worded it that way.

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Contents:
00:00 - Intro
02:12 - What are selections?
03:19 - Booleans
06:16 - Joining Booleans
07:55 - What is an index?
08:45 - Vertex Group Selection
10:14 - How floats are interpolated
11:30 - Float to Integer node
13:16 - Selections with Empties
16:27 - Index-based Selections
19:12 - Selecting a grid row
20:50 - Selecting a grid column
23:06 - Duplicate Index
24:55 - Mesh Island Index
26:10 - Index per point per island
28:11 - Splines
29:05 - Spline Parameter Index
30:47 - Index on Spline Domain
32:50 - Position-based Selections
35:19 - Normal-based Selections
37:15 - Raycasted Selections
40:10 - Curve Attribute Selections
42:20 - Curve Corner Selections
47:08 - Expand Selections
53:35 - Flatten Region Exercise

[shmuelisrl]

@Erindale, another tip 😁: when you were checking to see if any selection were too small you didn’t have to separate the mesh (which is some i try to avoid. [messes up my indices, attributes, extra compute time, etc]).

what you could do is the less well known node family called the "face groups to boundary edges" and "boundary edges to face groups". You first use the selection as a face group which you convert to boundary edges and then you convert it back; this gives you an ID per selection island, which you could usr with the accumulate field etc.

[herebtheend]

I use to think that I'll never get a grasp of Geometry nodes. But after watching this, I'm now certain of it.

[TripTilt]

one of the best, if not THE best, yet underrated, advanced yet prescinded geometry nodes tutorial. So very useful and valuable info! Thanks erin!!!

[Walthanar]

This video is pure gold in the form of zeros and ones travelling through the internet!

[totheknee]

32:17 - "Just a little bit of esoteric knowledge..." The very _best_ kind of knowledge there is!

[macronomicus]

I had many selection questions, you answered them all, and added lots more to consider. Excellent tutorial! Cheers!

[Erindale]

Correction: Accumulate Field node's "Total" output does not tell you how many elemtns have been counted, it returns the sum total of whatever values it has counted up. When the Value is 1 as in mine, that means it added 1 per element which is why I worded it that way.

[motionbones]

Selections… the topic i most need for GN! Many thanks.

[Chillerll]

You legend. This is the single best geo nodes tutorial I have seen and I wish I had it years ago.

[stache_obj]

oh shit this was exactly what i was looking for, for one of my projects. thanks a lot!
No one explains this complex node stuff better than you erin..

[danialsoozani]

The tutorial was amazing as always, but finding out the most common and still yet least spoken issue and making a tutorial for it was even more brilliant! great job and thanks a lot dear Erin :)

[zboy]

Really great video. Just to note that for the 'expand selection' part, the Blur Attribute also does the job when you put it through a Vector Math (Ceiling) node, so no need for the Repeat Zone. (or you can multiply instead of ceiling for a more circular expansion).

[johnsmith]

You are officially the best. Others abide our questions, you stand alone.

[cglifeforreal]

Thanks Erindale, Your videos are really helping me do things impossible to achieve with built in modifiers.
I hope you make a series about UV mapping especially mapping a "curve to mesh" geometry which uses a cyclic curve, I've been looking all around the web for a working solution but all of them work only in simple cases.

[JakeStaines]

Thank you so much for this. Both for excellently bridging the gap between a lot of other geometry node tutorials and Being Actually Useful, and also for using the word 'indices' repeatedly!

Seriously, I had a use-case I'd been trying to get geometry nodes to work for me on for a while and every time I tried I watched some introductory tutorial, went to have a play, and got nowhere and gave up - and it was always down to being able to actually pick apart the mesh to do the work on the right edges. I've been going back to it while watching this and it's already 90% of the way to where I need it.

[BBennie]

Been waiting for a tutorial on geometry nodes that goes over selections for quite some time now, Thank you!

[francesca]

I don't think I can thank you enough for this tutorial it's so helpfull

[Nicko]

Thanks for the brilliant tutorial, I did not realise the subtle power of the accumulate field node until I watched this, cheers!

[sudiptaroyarts]

As always, you're the only boss of the Geo nodes . 😊

[ClemensHoenig]

Great Tutorial. Thank you! To be honest, your tutorials keep pushing me to the limits, so I always need to watch them at least two times. Once I get it, it's really satisfying...