The Geometry Object

So you have decided to learn Houdini. You have a new scene open and you drop down a box. Now you want to change the divisions of the box. You see that there are several tabs in the parameter window for the box such as TransformMaterialRenderMisc but nowhere do you see the ability to change the subdivisions of the box. What gives? Welcome to the Geometry Object.

Object Level

One thing you have to remember is that in Houdini, when you drop down a Box or Sphere node at the object network level, that top level node is just a container for your actual geometry. The node you dropped into your network is actually a Geometry node. Select your node and have a look at its name in the parameter pane.

Geometry Object
Geometry Object

 

If you’re familiar with Cinema 4D, you have probably created hierarchies consisting of Mograph or Deformer objects that are nested under a Null object. Well, the Null object is your container. You can move that sucker around and even copy and paste it into another scene and all the objects within its hierarchy come along for the ride. The Geometry object in Houdini acts in a similar way.1

Diving In

The nodes that live within the Geometry node make up your actual geometry objects. You can have boxes, spheres, grids or custom objects all contained with this node. These nodes are called Surface Operators or better know as SOPs. You can do all types of funky things to the geometry in here. Now you can drop some Houdini lingo at the next office party!

So if you select your Geometry object and press the Enter key or the i key, you will go inside the node and see the Box node. If you look at your Parameter Pane you should see various options for your box such as Primitive Type, Divisions, etc. You can now start connecting nodes to this box node. If you want to jump back up to Object level, you hit the letter u.

Box object
Box object

 

You can also navigate the hierarchy by using the Gadget Path at the top of the Parameter Pane. There is also some text on the top left hand side of the Parameter Pane that tells you in which Context you are in. As you can see from the image below, you are currently inside a DOP Network node which throws you into a Dynamics Context.

The Houdini Hierarchy
The Houdini Hierarchy

 

Object Level Options

So knowing this, is there another way to access these options at the Object Level without having to dive into the node? Of course! If your camera icon is selected, hit the Enter key while your mouse hovers over the viewport to activate the Handles tool. It’s important your mouse is over the viewport, otherwise you will just dive into the node if one is selected. Once activated, the Handles tool will give you some options along the top of the viewport. These options will go away if the tool becomes deactivated so keep an eye out for that. Another caveat, this is really only useful when you first drop your Primitive since it needs to be the active node inside the hierarchy.

Object Level options
Object Level options

 

There you have it in a nutshell! It’s a rather superficial overview but it should give you a bit more confidence to explore on your own. There is plenty more to learn but at least you know what the deal is with that Geometry object that gets placed at the Object level. The same concept applies to the other primitives. Try dropping an actual Geometry node at the Object level and dive in. Why is that file node in there? Can you delete it and add something else?


1. I’m giving you a layman’s explanation on all this without getting into the technical details.

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990adjustments

990adjustments

I am a motion designer & developer based out of South Florida.
When not designing or animating pixels, I wrangle some code. If all else fails, I watch Twilight Zone, I Love Lucy, or Three’s Company reruns.