What is the "op:" ?

[jungjaehwa]

Hello.

I am Jamie.

I would like to ask about op: in Houdini.

I found help document about that.

http://localhost:48626/io/op_syntax

You can see bold underlining below help document a part.

Here are my question. A file and a file name! What is correctly that mean?

I guess that a file is baked data on disk as bgeo, geo with ROP Output Driver SOP. Right?

Please let me know.

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Import and export How to use data from a node instead of a file (op:)

Overview

In various places in Houdini, nodes may have a parameter which expects a file name of a file containing a specific type of data.

In these types of parameters you can usually use op:/path/to/node instead of a file name to grab data from live nodes in the scene hierarchy instead of from a file.

For example, the Volume Sample from File VOP gets the value at a certain position in a volume.

It has a Geometry file parameter for a volume file name, but you could sample a volume in a SOP network instead of a file on disk using something like:

op:/geo1/volume1

...as the value of the Geometry file parameter.

This works for (at least) the following common file types:

* Geometry file: surface node (SOP)

* Image file: compositing node (COP)

* Channel data file: channel node (CHOP)

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Edited December 26, 2012 by jungjaehwa

[ranxerox]

it just means that if you have a filename parameter, you can point it to a node instead of a file on disk. For instance, if you have a vop sop which has a file parameter (to a pointcloud on disk for instance), in that filename parameter you can put an "op" string instead, eg.: op:/obj/node1/OUT. One quirky thing about the op syntax is that the path cannot be relative, so be sure it evaluates to an absolute path in your scene.

-G

[jungjaehwa]

Hello, Gregory!

Thank you so much for your help.

I am understanding.

Have a great day.

Edited December 27, 2012 by jungjaehwa

[jungjaehwa]

I have a more question about the filename parameter and file parameter.

Is that mean that the name of the attribute as attached?

[ranxerox]

I don't understand the question. What you have there is unrelated to the previous question. "attribute1" is the name of the attribute you are creating.

-G

I have a more question about the filename parameter and file parameter.

Is that mean that the name of the attribute as attached?