What is Solaris?
Solaris is a set of look development, layout, and lighting tools provided by Houdini for creating USD-based scene graphs. Solaris is integrated with USD’s Hydra Imaging Framework to access renderers such as V-Ray, Karma, etc. Read more here.
What is Hydra?
Hydra is a rendering framework that passes the data from the DCC’s scene graph to the renderer. Hydra acts as an interactive rendering mode for USD. Having Hydra support doesn’t automatically mean USD support and vice-versa, as each method requires development on its own.
What is a Hydra scene delegate?
The Hydra delegate that ships with V-Ray for Houdini is able to work both as an interactive render delegate for Houdini’s Solaris viewport, and as a standalone tool for final batch rendering through Houdini’s husk executable.
What is Hydra render delegate?
A render delegate parses the scene data provided by the Hydra API to do the actual rendering. Chaos V-Ray is available as a render delegate in Solaris.
The V-Ray Hydra delegate can be used both in Solaris for Viewport IPR rendering, and through the standalone Husk executable shipped with Houdini, for production rendering.
Where can I find the V-Ray Hydra delegate?
V-Ray Hydra delegate appears in Houdini’s viewport options menu.
You can also use the V-Ray Hydra delegate for production rendering through Husk. Husk is found under the Houdini installation folder/bin/husk.exe
To use V-Ray, you should call the following in a terminal:
husk.exе -R HdVRayRendererPlugin
Is Husk based on Hydra and is it executing it under the hood?
Husk renders a USD file using a Hydra client, such as Karma or V-Ray. The Husk renderer is a standalone tool included in Houdini that can be used for batch rendering with any Hydra delegate (e.g. V-Ray).
Does the render delegate refer to both Hydra (viewport) and Husk?
Hydra is an open-source framework to transport live scene graph data to renderers. Hydra is also used when doing batch rendering with Husk.
What is USD?
USD or Universal Scene Description is an open-source interchange format developed by Pixar and contributed to by industry-leading studios. This format is designed to support almost any type of 3D scene and animation data and transport it between 3D creation tools, assembly tools, and pipeline utilities. Besides interoperability, USD enables non-destructive iterations and new assembly workflow scenarios. USD also allows a renderer to attach its data to the scene description so the definitions and assignments of shaders, materials, lights, cameras, and environments persist within the USD file. Read more about USD here.
What USD file formats are supported?
The supported USD file formats are:
- .usd (can be either human-readable ASCII or binary)
- .usda (human-readable ASCII)
- .usdz (a ZIP version of a USD file, with the associated assets inside of it)
USD also includes support for reading and writing Alembic files.
Do I need to install additional plugins to render with V-Ray in Solaris?
No, you don’t need to install additional plugins or builds beyond the standard V-Ray executable build.
Which features are supported in Solaris?
A full list of all supported features for rendering in Solaris with V-Ray can be found on the Solaris Features and Limitations page.
Can V-Ray render MaterialX materials?
Yes, the V-Ray render delegate can render MaterialX (.mtlx) materials. The full list of all supported mtlx nodes can be found on the MaterialX Support page. Read more about MaterialX here.
Does V-Ray support importing scene data from SOPs (e.g. through the Scene Import LOP)?
It is recommended to build your scene in the /stage context. Building scenes using the 'vanilla' Houdini workflow and importing in /stage through the Scene Import LOP is partially supported, and there are edge cases where the Scene Import will fail to parse the material assignments for V-Ray shaders.
Can V-Ray perform distributed rendering in Solaris?
Yes.
Can V-Ray resume rendering after stopping?
Yes.
Can I override materials in Solaris and how?
Yes, you can override any V-Ray material through the spreadsheet with a right-click. You can also override other materials, except for the V-Ray ones, through the Edit Material Network LOP node in /stage.
Can I promote V-Ray material parameters in Solaris?
Yes.
Can I use multi-render workflows with V-Ray in Solaris?
Yes, you can. For example, if you want to render materials specific for different renderers, e.g. V-Ray materials and Karma materials, you need to plug the materials into a Collect VOP node.
Why can’t I see my V-Ray Proxy after import in Solaris?
V-Ray Proxy cannot be previewed in Solaris viewport and is seen only during render time.
How do I turn off the light from the class prim system? Only its instances should emit light.
Disable the light by turning off the Enabled parameter. The instancer then will enable the instanced lights. Note that this behavior will be fixed in the future.