Houdini

OpenPype global tools

• Work Files
• Create
• Load
• Manage (Inventory)
• Publish
• Library Loader

Publishing Alembic Cameras

You can publish baked camera in Alembic format.

Select your camera and go OpenPype -> Create and select Camera (abc). This will create Alembic ROP in out with path and frame range already set. This node will have a name you've assigned in the Creator menu. For example if you name the subset Default, output Alembic Driver will be named cameraDefault. After that, you can OpenPype -> Publish and after some validations your camera will be published to abc file.

Publishing Composites - Image Sequences

You can publish image sequences directly from Houdini's image COP networks.

You can use any COP node and publish the image sequence generated from it. For example this simple graph to generate some noise:

To publish the output of the radialblur1 go to OpenPype -> Create and select Composite (Image Sequence). If you name the variant Noise this will create the /out/imagesequenceNoise Composite ROP with the frame range set.

When you hit Publish it will render image sequence from selected node.

Use selection

With Use selection is enabled on create the node you have selected when creating will be the node used for published. (It set the Composite ROP node's COP path to it). If you don't do this you'll have to manually set the path as needed on e.g. /out/imagesequenceNoise to ensure it outputs what you want.

Publishing Point Caches (alembic)

Publishing point caches in alembic format is pretty straightforward, but it is by default enforcing better compatibility with other DCCs, so it needs data do be exported prepared in certain way. You need to add path attribute so objects in alembic are better structured. When using alembic round trip in Houdini (loading alembics, modifying then and then publishing modifications), path is automatically resolved by alembic nodes.

In this example, I've created this node graph on sop level, and I want to publish it as point cache.

Note: connectivity will add index for each primitive and primitivewrangle1 will add path attribute, so it will be for each primitive (sphere1 and sphere2) as Maya is expecting - strange_GRP/strange0_GEO/strange0_GEOShape. How you handle path attribute is up to you, this is just an example.

Now select the output0 node and go OpenPype -> Create and select Point Cache. It will create Alembic ROP /out/pointcacheStrange

Publishing Reviews (OpenGL)

To generate a review output from Houdini you need to create a review instance. Go to OpenPype -> Create and select Review.

On create, with the Use Selection checkbox enabled it will set up the first camera found in your selection as the camera for the OpenGL ROP node and other non-cameras are set in Force Objects. It will then render those even if their display flag is disabled in your scene.

Redshift

Work in progress

This part of documentation is still work in progress.

USD (experimental support)

Publishing USD

You can publish your Solaris Stage as USD file.

This is very simple test stage. I've selected output lop node and went to OpenPype -> Create where I've selected USD. This created /out/usdDefault USD ROP node.

Publishing USD render

USD Render works in similar manner as USD file, except it will create USD Render ROP node in out and will publish images produced by it. If you have selected node in Solaris Stage it will by added as lop path to ROP.

Publishing VDB

Publishing VDB files works as with other data types. In this example I've created simple PyroFX explosion from sphere. In pyro_import I've converted the volume to VDB:

I've selected vdb1 and went OpenPype -> Create and selected VDB Cache. This will create geometry ROP in /out and sets its paths to output vdb files. During the publishing process whole dops are cooked.

Publishing Houdini Digital Assets (HDA)

You can publish most of the nodes in Houdini as hda for easy interchange of data between Houdini instances or even other DCCs with Houdini Engine.

Creating HDA

Simply select nodes you want to include in hda and go OpenPype -> Create and select Houdini digital asset (hda). You can even use already existing hda as a selected node, and it will be published (see below for limitation).

HDA Workflow limitations

As long as the hda is of same type - it is created from different nodes but using the same (subset) name, everything is ok. But once you've published version of hda subset, you cannot change its type. For example, you create hda Foo from Cube and Sphere - it will create hda subset named hdaFoo with the same type. You publish it as version 1. Then you create version 2 with added Torus. Then you create version 3 from the scratch from completely different nodes, but still using resulting subset name hdaFoo. Everything still works as expected. But then you use already existing hda as a base, for example from different artist. Its type cannot be changed from what it was and so even if it is named hdaFoo it has different type. It could be published, but you would never load it and retain ability to switch versions between different hda types.

Loading HDA

When you load hda, it will install its type in your hip file and add published version as its definition file. When you switch version via Scene Manager, it will add its definition and set it as preferred.