Using geometry nodes, how can I toggle between different geometries, similar to shader editor?

Question

One feature that I use frequently in shader editor, is an option to toggle between different shaders or textures. It can look like this:

Changing the value node on the left within the interval of 0.0 to 0.3 allows me to quickly change the used diffuse shader. This setup can be used for a lots of stuff.

How can I replicate this setup in geometry nodes with the intention of changing different geometries?

Let's say I have a cube, sphere and a monkey in my scene and I add a geometry nodes to the cube. The other two objects are loaded using object info nodes. Since Join Geometry node doesn't have a factor, I can't really switch between used geometry.

Answer 1

You can do that quite easy with a Point Separate node.

In the image above I've created a mesh with a single vertex. The node network splits into two paths based on the attribute value do_monkey, which is set by the Attribute Fill node (or by anything else that you need).

Answer 2

The Switch Node

The Switch Node can be set to receive the following input types:

• Float
• Integer
• Boolean
• Vector
• String
• Color
• Object
• Image
• Geometry
• Collection
• Texture
• Material

Here are two different approaches you can take: Switching between geometries, or switching between objects. If switching between objects, by using Relative transformations, you can also access Location/Rotation/Scale data.

In this example, changing the Switch value from 0 to 1 will change the evaluation from FALSE to TRUE, resulting in a Cone being received from the Switch Node set to Geometry, and a Suzanne monkey mesh from the Switch Node set to Object.

Multi-switch

If you need to cycle through many different objects or geometries, you can create a Group Node that accepts multiple inputs, and select one as the output:

Here's what's happening inside the group:

Yikes!

It's not as complex as is looks. Just a series of TRUE or FALSE evaluations, matching against the integer value of the "Select Object" input.

^{(It's not obvious from the screenshot, but the collapsed nodes are Math Nodes set to Add)}

No, you don't need to reconstruct it: _{(Made using Blender 3.0.1)}

Result:

Answer 3

You can try a more modular approach. Start by creating a node group with a switch system. Checking if the modifier index is the same as the node group index. If yes, output the object geometry, if not, output empty geometry.

This lets you create intricate setups because you can use the node group index however you want. You can set an object to appear on two different indices, or two objects to appear on a single index.

Using this setup in the modifier :

BTW the setup in the shader example isn't linearly switching between the shaders. The blue diffuse shader has as much weight as all the other shaders combined. But for integer values it's okay. And I would clamp the Math nodes, mixing with a negative factor can get funky. :)