Started learning Houdinin 9.1, and I think it is an awesome app. Somewhat intimidating, but I am actually starting to really enjoy its power the more I use it.

A number of tuts from here and Digital Tutors have instructed to delete the file object from a SOP/DOP during an excercise. I don't understand the purpose behind this.

For exmple in the Stamp tut from here, he creates a Geometry objext then deletes the file object. Huh?

What is “create in context?” Why use it?

Lastly, how to I make my viewport black as in the tuts from here?

Ruteger
A number of tuts from here and Digital Tutors have instructed to delete the file object from a SOP/DOP during an excercise. I don't understand the purpose behind this.

For exmple in the Stamp tut from here, he creates a Geometry objext then deletes the file object. Huh?

These would be pre-Houdini9 tutorials. It should still be the same in Houdini9 where you can tab-type geometry in a network at the Object level then dive in to that object in to SOPs and remove the default File SOP that is fetching the defgeo.bgeo box from disk.

Ruteger
What is “create in context?” Why use it?

Create in Context vs. Create at Object level is all about control over where you want to add the actual SOP building or modifying your geometry.
The default is Create at Object Level.

Let's take a look at creating a Sphere.
If I have Create at Object Level on, no matter where I access the Sphere tool from, a new object will be created and inside that object is the Sphere SOP creating my geometry.

If you have Create in Context on, there are several possible outcomes.

If you are at the object level and you press the sphere tool from the shelf or from the tab menu in the viewport, you will create a new object and inside that object is the Sphere SOP

If you are at the Geometry SOP level and you hit the sphere tool from the shelf, from the tab menu or in the network, you will add a Sphere SOP inside the current object. Now you will have to use a Merge SOP to add the Sphere to any other geometry in that object.


It's all about control and flexibility as well as shielding new users from having to manage SOPs right off the bat. It is quite common for a Houdini user as they get more proficient to change this option to “Create in Context” as they are more aware of where they are: Object vs. Geometry (SOPs).

Ruteger
Lastly, how to I make my viewport black as in the tuts from here?

In the viewport preferences.
With your cursor over the viewport, hit the d key.
Go to the Background folder and in the upper right change the Color Scheme to Dark.

Jeff beat me…

So we are deleting the file object because we don't want to reference defgeo.bgo, but the new geometry we will create such as a line, etc.?

If you lay down a Geometry node the file SOP is standard in the Geometry node. You could leave it if you want and add your own geometry.

Ruteger
So we are deleting the file object because we don't want to reference defgeo.bgo, but the new geometry we will create such as a line, etc.?

Yes exactly.

In Houdini an Object is actually just an empty container. It doesn't “predetermine” what is inside it.

What is somewhat bizarre to Maya artists coming over to Houdini is that you can actually have a Geometry node with no shape attached to it. Houdini is also quite different in that you can easily have points with no primitive information (Add SOP add a single point), mix polygon with NURBs curves and skin them to form a NURBs surface, etc. Lots of cool things await you.

By default a fresh Geometry Object is exactly the way that Pagefan described.