Geo Nodes / Frames - pick from random object collection, distribute on surface

[Turner]

Hi all,

Just getting started learning Geometry Nodes / Frames and am trying to figure a few things out.

My goal is to distribute collections as instances on objects.

1. How can I add a Collection to a Geometry Node? (Or a stand-alone object?)

2. Is there a way to choose randomly from different collections?

thanks!

[DNorman]

Hi
1- use the “collection info” node to enter a collection in a GN tree.

2- here I have 2 collections one has 3 red round things the other 3 blue cube-ish things
I separate the points of the grid randomly and use the selection to instance one collection (randomly) on the points and the inverted selection to do the same with the other collection.
There are probably other ways to do it.

Edit:
The range of the random objects in each collection depends on the amount of objects in each collection in this case 0, 1 or 2

Edit 2: sorry the random node for the grid point selection could simply be 0-1 ( yes or no )
If you increase the max or decrease the min it will bias the selection.

Edit 3

I have just realised that you probably want to distribute the objects randomly on the faces instead of evenly on the points of the mesh. In which case you can use the distribute points on faces node.

You can also choose to assign points to different collections with the compare node in this example I have 2 collections and 2 options.

As I said there are probably other way to do all this, I hope this gives you ideas.

[Turner]

Nice!! Going to try this out. Thanks so much!

[Turner]

Hi again @DNorman -

(edit… nevermind)

Wasn’t sure where to put the geometry nodes… as it is, I found I can create Node arrangement attached to a cube, for example, and simply hide the cube.

Experimenting now…

cheers

[Turner]

Ok, this is insanely fun. Puzzling, but fun…

Questions about Random Value:

1. Why does it go -3 to 3 rather than 1 to 3?
2. How do we get it to fill all spaces with something?

Back to experimenting…

[DNorman]

Sorry for the late reply I have been working.

@Turner

Why does it go -3 to 3 rather than 1 to 3?

Yes that was a mistake thus my “edit 2”

@DNorman

Edit 2: sorry the random node for the grid point selection could simply be 0-1 ( yes or no )
If you increase the max or decrease the min it will bias the selection.

Here is a new screenshot of the first setup (0-1.)

With this first setup there should always be one random object on every point/vertex of the grid.

The second setup distributes objects randomly on faces with a density factor and there will be some spaces with lower values, the higher the density factor the more objects and less spaces there will be.
When using random distribution on faces you will find that some objects will overlap. This is not so easy to avoid you could take a look at this thread:

Geometry nodes - instances overlapping

Hello, as part of my quest to stop modelling absolutely everything as separate shapes I’m delving into geometry nodes. I have a simple setup as the basis for a rough drystone wall. I’ve instanced a simple cube to a plane with some randomness in the scale, and have the points distributed using the poisson disk mode but the instanced cubes overlap in places. Is there a way to avoid the instances overlapping? I’ve played with the poisson disk settings but still have some overlapping cubes. For cl…

There has also been talk about this overlapping in the (huge) GN node thread, unfortunately the information is randomly spread on that thread and it is not so easy to follow.

Geometry Nodes

Anyone know how to get the second closest point using the geometry proximity node? I am trying to find points that are close together to offset them and avoid overlap, so I want to run geo prox on itself, but this returns 0, as each individual point is indeed in the exact same spot. any ideas?

@Turner

Ok, this is insanely fun. Puzzling, but fun…

GN node are fun, I am only scratching the surface myself, at first they were very “daunting” but little by little I am trying to get the concepts together.
I always recommend Erindale’s channel on you tube for node things, he is really good at explaining things.

https://www.youtube.com/channel/UCGMyyn2FdEFcDfP1wQRh5lQ

Be careful not to watch old GN tutorials (from before the rewrite “fields system”) 3.0 up is the new system.