A Complete Guide to Solid Angle Houdini to Arnold v5.0.2 for Houdini 17.x 18.x Win Mac
<table>
<tr>
<td>
<h1>Introduction</h1>
<p>If you are a 3D artist or animator who uses Houdini, you might be interested in Solid Angle Houdini to Arnold (HtoA), a plugin that provides a tight bridge to the Arnold renderer from within the standard Houdini interface. Arnold is an advanced Monte Carlo ray tracing renderer that helps you deliver beautiful and predictable results for feature-length animation and visual effects.</p>
Solid Angle Houdini to Arnold v5.0.2 for Houdini 17.x 18.x Win Mac
<p>HtoA allows you to use all the features of Arnold in a way that is familiar to both Houdini users and Arnold users in Maya or Softimage. It also enables smooth lighting workflows between Houdini and other DCC applications, since setups can be exported and shared. With HtoA, you can create stunning photorealistic images, animations, and simulations with ease and efficiency.</p>
<p>In this article, we will introduce you to the latest version of HtoA, v5.0.2, which was released on January 27, 2020. We will show you how to install and activate it, how to use it in Houdini, and how to get the most out of it with some tips and tricks. By the end of this article, you will have a better understanding of how HtoA can enhance your 3D workflow and creativity.</p>
<h2>How to install and activate HtoA</h2>
<p>The first step to use HtoA is to download and install it on your computer. You can find the download links for Windows and Mac on the official website. You will need a valid license key or a license server to activate it.</p>
<p>To install HtoA on Windows, follow these steps:</p>
<ol>
<li>Download the installer for your version of Houdini (17.x or 18.x) from the website.</li>
<li>Run the installer as administrator and follow the instructions.</li>
<li>Select the components you want to install (HtoA plugin, Arnold SDK, etc.).</li>
<li>Specify the installation folder for HtoA.</li>
<li>Specify the installation folder for Arnold SDK (if not installed already).</li>
<li>Specify the license type (single-user or network).</li>
<li>If you choose single-user, enter your license key when prompted.</li>
<li>If you choose network, enter your license server address when prompted.</li>
<li>Finish the installation.</li>
</ol>
<p>To install HtoA on Mac, follow these steps:</p>
<ol>
<li>Download the installer for your version of Houdini (17.x or 18.x) from the website.</li>
<li>Open the installer package and follow the instructions.</li>
<li>Select the components you want to install (HtoA plugin, Arnold SDK, etc.).</li>
<li>Specify the installation folder for HtoA.</li>
<li>Specify the installation folder for Arnold SDK (if not installed already).</li>
<li>Specify the license type (single-user or network).</li>
<li>If you choose single-user, enter your license key when prompted.</li>
<li>If you choose network, enter your license server address when prompted.</li>
<li>Finish the installation.</li>
</ol>
<p>After installing HtoA, you can launch Houdini and check if the plugin is loaded correctly. You should see a new shelf called Arnold with several buttons for HtoA functions. You should also see a new menu called Arnold in the main menu bar. If you don't see them, you might need to manually set the environment variables for HtoA. You can find the instructions on how to do that on the website.</p>
<h3>How to use HtoA in Houdini</h3>
<p>Now that you have installed and activated HtoA, you can start using it in your Houdini projects. HtoA integrates seamlessly with Houdini's interface and workflow, so you don't need to learn a new software. You can use HtoA to create and assign Arnold materials and shaders, set up Arnold lights and cameras, render with Arnold in the viewport and in the render view, and export and import Arnold scenes and assets.</p>
<h4>How to create and assign Arnold materials and shaders</h4>
<p>One of the main advantages of HtoA is that it gives you access to the powerful and flexible Arnold material system. You can create realistic and complex materials and shaders using nodes and networks in Houdini's material context. You can also use presets and libraries of Arnold materials and shaders that are included with HtoA or downloaded from online sources.</p>
<p>To create an Arnold material, you can use one of these methods:</p>
<ul>
<li>Click on the Arnold Material button on the Arnold shelf. This will create a new material network with an Arnold Standard Surface shader inside.</li>
<li>Go to the Material Palette tab in the network editor and drag and drop an Arnold material node into the network.</li>
<li>Right-click on an empty space in the network editor and choose Create > Arnold > Material from the context menu.</li>
</ul>
<p>To assign an Arnold material to an object, you can use one of these methods:</p>
<ul>
<li>Select the object in the viewport or in the network editor and click on the Assign Material button on the Arnold shelf. This will open a dialog where you can choose an existing material or create a new one.</li>
<li>Select the object in the viewport or in the network editor and drag and drop a material node from the network editor onto it.</li>
<li>Select the object in the viewport or in the network editor and go to its parameters panel. Under the Render tab, expand the Material section and click on the arrow next to Shop Material Path. This will open a dialog where you can choose an existing material or create a new one.</li>
</ul>
<p>To edit an Arnold material, you can double-click on its node in the network editor or select it and press Enter. This will open its parameters panel where you can adjust its settings and properties. You can also dive inside its node network by double-clicking on it or pressing I. This will allow you to add, remove, or modify nodes that define the material's behavior.</p> <h4>How to set up Arnold lights and cameras</h4>
<p>Another benefit of HtoA is that it lets you use the native Arnold lights and cameras in your Houdini scenes. These are specially designed for Arnold and offer more features and options than the default Houdini lights and cameras. You can also use Houdini lights and cameras with HtoA, but they will be automatically converted to Arnold lights and cameras at render time.</p>
<p>To create an Arnold light, you can use one of these methods:</p>
<ul>
<li>Click on the Arnold Light button on the Arnold shelf. This will create a new light object with an Arnold light node inside.</li>
<li>Go to the Lights and Cameras tab in the network editor and drag and drop an Arnold light node into the network.</li>
<li>Right-click on an empty space in the network editor and choose Create > Arnold > Light from the context menu.</li>
</ul>
<p>To edit an Arnold light, you can select it in the viewport or in the network editor and press Enter. This will open its parameters panel where you can adjust its settings and properties. You can also dive inside its node network by double-clicking on it or pressing I. This will allow you to add, remove, or modify nodes that define the light's behavior.</p>
<p>To create an Arnold camera, you can use one of these methods:</p>
<ul>
<li>Click on the Arnold Camera button on the Arnold shelf. This will create a new camera object with an Arnold camera node inside.</li>
<li>Go to the Lights and Cameras tab in the network editor and drag and drop an Arnold camera node into the network.</li>
<li>Right-click on an empty space in the network editor and choose Create > Arnold > Camera from the context menu.</li>
</ul>
<p>To edit an Arnold camera, you can select it in the viewport or in the network editor and press Enter. This will open its parameters panel where you can adjust its settings and properties. You can also dive inside its node network by double-clicking on it or pressing I. This will allow you to add, remove, or modify nodes that define the camera's behavior.</p> <h4>How to render with Arnold in the viewport and in the render view</h4>
<p>One of the most convenient features of HtoA is that it allows you to render with Arnold in the Houdini viewport and in the render view. This gives you instant feedback and interactivity while you work on your scene. You can see how your materials, lights, cameras, and other elements look in Arnold without having to export or save anything.</p>
<p>To render with Arnold in the viewport, you can use one of these methods:</p>
<ul>
<li>Click on the Arnold Render button on the Arnold shelf. This will switch the viewport to the Arnold Render mode and start rendering.</li>
<li>Go to the viewport menu and choose Render > Arnold Render. This will switch the viewport to the Arnold Render mode and start rendering.</li>
<li>Press F5 on your keyboard. This will switch the viewport to the Arnold Render mode and start rendering.</li>
</ul>
<p>To stop rendering with Arnold in the viewport, you can use one of these methods:</p>
<ul>
<li>Click on the Stop button on the Arnold shelf. This will stop rendering and switch the viewport back to the previous mode.</li>
<li>Go to the viewport menu and choose Render > Stop Rendering. This will stop rendering and switch the viewport back to the previous mode.</li>
<li>Press Esc on your keyboard. This will stop rendering and switch the viewport back to the previous mode.</li>
</ul>
<p>To render with Arnold in the render view, you can use one of these methods:</p>
<ul>
<li>Click on the Render View button on the Arnold shelf. This will open a new window with the render view and start rendering.</li>
<li>Go to the main menu bar and choose Render > Render View. This will open a new window with the render view and start rendering.</li>
<li>Press F9 on your keyboard. This will open a new window with the render view and start rendering.</li>
</ul>
<p>To stop rendering with Arnold in the render view, you can use one of these methods:</p>
<ul>
<li>Click on the Stop button on the render view toolbar. This will stop rendering and pause the image.</li>
<li>Go to the render view menu and choose Render > Stop Rendering. This will stop rendering and pause the image.</li>
<li>Press Esc on your keyboard. This will stop rendering and pause the image.</li>
</ul>
<p>To resume rendering with Arnold in the render view, you can use one of these methods:</p>
<ul>
<li>Click on the Resume button on the render view toolbar. This will resume rendering from where it stopped.</li>
<li>Go to the render view menu and choose Render > Resume Rendering. This will resume rendering from where it stopped.</li>
<li>Press F9 on your keyboard. This will resume rendering from where it stopped.</li>
</ul> <h4>How to export and import Arnold scenes and assets</h4>
<p>Another useful feature of HtoA is that it allows you to export and import Arnold scenes and assets in various formats. This can help you save time and disk space, as well as share your work with other artists or applications. You can export and import Arnold scenes and assets using the Arnold shelf, the Arnold menu, or the Arnold ROP node.</p>
<p>To export an Arnold scene, you can use one of these methods:</p>
<ul>
<li>Click on the Export Scene button on the Arnold shelf. This will open a dialog where you can choose the file name, format, and options for the exported scene.</li>
<li>Go to the Arnold menu and choose Export > Scene. This will open a dialog where you can choose the file name, format, and options for the exported scene.</li>
<li>Create an Arnold ROP node in the output context and connect it to the output of your scene network. In the parameters panel of the Arnold ROP node, choose Scene as the driver type and specify the file name, format, and options for the exported scene. Then press Render to export the scene.</li>
</ul>
<p>To import an Arnold scene, you can use one of these methods:</p>
<ul>
<li>Click on the Import Scene button on the Arnold shelf. This will open a dialog where you can choose the file name and options for the imported scene.</li>
<li>Go to the Arnold menu and choose Import > Scene. This will open a dialog where you can choose the file name and options for the imported scene.</li>
<li>Create an Arnold Procedural node in the geometry context and specify the file name and options for the imported scene in its parameters panel. Then place it in your scene network as a geometry object.</li>
</ul>
<p>To export an Arnold asset, you can use one of these methods:</p>
<ul>
<li>Click on the Export Asset button on the Arnold shelf. This will open a dialog where you can choose the file name, format, and options for the exported asset.</li>
<li>Go to the Arnold menu and choose Export > Asset. This will open a dialog where you can choose the file name, format, and options for the exported asset.</li>
<li>Create an Arnold ROP node in the output context and connect it to the output of your asset network. In the parameters panel of the Arnold ROP node, choose Asset as the driver type and specify the file name, format, and options for the exported asset. Then press Render to export the asset.</li>
</ul>
<p>To import an Arnold asset, you can use one of these methods:</p>
<ul>
<li>Click on the Import Asset button on the Arnold shelf. This will open a dialog where you can choose the file name and options for the imported asset.</li>
<li>Go to the Arnold menu and choose Import > Asset. This will open a dialog where you can choose the file name and options for the imported asset.</li>
<li>Create an Arnold Procedural node in the geometry context and specify the file name and options for the imported asset in its parameters panel. Then place it in your scene network as a geometry object.</li>
</ul>
<h4>Tips and tricks for HtoA</h4>
<p>In this section, we will share some tips and tricks that can help you improve your HtoA experience and results. These are based on the official documentation, the online tutorials, and the user forums. You can also find more tips and tricks on these sources and other online resources.</p>
<h5>How to optimize rendering performance and quality</h5>
<p>Rendering with Arnold can be fast and efficient, but it can also be demanding and time-consuming, depending on your scene complexity and settings. Here are some general guidelines that can help you optimize your rendering performance and quality:</p>
<ul>
<li>Use the Adaptive Sampling feature to automatically adjust the number of samples per pixel based on the noise level. This can reduce the overall render time and noise without compromising quality. You can enable Adaptive Sampling in the Sampling tab of the Arnold ROP node or the Arnold Render Settings window.</li>
<li>Use the Auto Bump Mapping feature to automatically convert displacement maps to bump maps when the displacement is too small to be noticeable. This can save memory and speed up rendering without affecting the appearance. You can enable Auto Bump Mapping in the Subdivision tab of the Arnold ROP node or the Arnold Render Settings window.</li>
<li>Use the OptiX Denoiser feature to automatically remove noise from your renders using NVIDIA's AI-accelerated denoising technology. This can improve the quality of your renders with fewer samples and faster render times. You can enable OptiX Denoiser in the AOVs tab of the Arnold ROP node or the Arnold Render Settings window.</li>
<li>Use the Arnold Scene Source feature to cache your scene data into a single file that can be loaded by Arnold at render time. This can reduce the overhead of sending data from Houdini to Arnold and speed up rendering. You can enable Arnold Scene Source in the Scene tab of the Arnold ROP node or the Arnold Render Settings window.</li>
<li>Use the Profiling feature to analyze your render statistics and identify potential bottlenecks or issues in your scene. This can help you troubleshoot and optimize your scene for better performance and quality. You can enable Profiling in the System tab of the Arnold ROP node or the Arnold Render Settings window.</li>
</ul>
<h5>How to use Arnold operators and procedurals</h5>
<p>Arnold operators and procedurals are powerful features that allow you to manipulate or generate scene data at render time using nodes and networks. You can use them to create complex effects, such as instancing, scattering, shading, overriding, etc., that would be difficult or impossible to achieve otherwise.</p>
<p>To use Arnold operators, you need to create an Arnold Operator node in the output context and connect it to the output of your scene network. In the parameters panel of the Arnold Operator node, you can choose from various types of operators, such as Collection, MaterialX, Override, etc., and specify their settings and properties. You can also dive inside its node network by double-clicking on it or pressing I. This will allow you to add, remove, or modify nodes that define the operator's behavior.</p>
<p>To use Arnold procedurals, you need to create an Arnold Procedural node in the geometry context and specify the file name and options for the procedural in its parameters panel. Then place it in your scene network as a geometry object. You can choose from various types of procedurals, such as Alembic, ASS, USD, etc., and load them from external files or from Houdini's internal cache.</p>
<h5>How to use Arnold AOVs and LPEs</h5>
<p>Arnold AOVs and LPEs are advanced features that allow you to output and control different aspects of your render, such as diffuse, specular, depth, motion vector, etc., into separate images or channels. You can use them to fine-tune your render quality, adjust your lighting and shading, or apply post-processing effects.</p>
<p>To use Arnold AOVs, you need to go to the AOVs tab of the Arnold ROP node or the Arnold Render Settings window. There you can add, remove, or modify AOVs using the AOV Browser. You can also create custom AOVs using the AOV Write nodes in your material networks. You can specify the file name, format, and options for each AOV in its parameters panel.</p>
<p>To use Arnold LPEs, you need to create an LPE AOV in the AOV Browser and specify its expression in its parameters panel. LPE stands for Light Path Expression, which is a syntax that allows you to define what light paths you want to output in your AOV. For example, you can use LPEs to isolate direct or indirect lighting, specific light or object groups, or specific material components.</p>
<h5>How to use Arnold denoiser and post-processing effects</h5>
<p>Arnold denoiser and post-processing effects are additional features that allow you to enhance your render quality and appearance without increasing your render time or samples. You can use them to remove noise, add bloom, glare, color correction, tone mapping, etc., to your render.</p>
<p>To use Arnold denoiser, you need to enable it in the AOVs tab of the Arnold ROP node or the Arnold Render Settings window. You can choose between the OptiX Denoiser or the Noice Denoiser, depending on your hardware and preference. You can also adjust the denoiser settings and options in their parameters panels.</p>
<p>To use Arnold post-processing effects, you need to enable them in the Post tab of the Arnold ROP node or the Arnold Render Settings window. There you can add, remove, or modify post-processing effects using the Post FX Browser. You can also adjust the post-processing effects settings and options in their parameters panels.</p>
<h6>Conclusion</h6>
<p>In this article, we have introduced you to Solid Angle Houdini to Arnold (HtoA), a plugin that provides a tight bridge to the Arnold renderer from within the standard Houdini interface. We have shown you how to install and activate it, how to use it in Houdini, and how to get the most out of it with some tips and tricks.</p>
<p>We hope that this article has helped you understand how HtoA can enhance your 3D workflow and creativity. If you want to learn more about HtoA, you can visit the official website, where you can find the documentation, the tutorials, the forum, and more. You can also download a free trial version of HtoA and try it for yourself.</p>
<p>Thank you for reading this article and