Official documentation of the Megascans Plugin for SideFX Houdini

Overview

The Megascans plugin for Houdini allows you to  set up Megascans assets automatically with a single click inside Houdini.

It currently supports only the very latest versions of the following render engines and shader set ups for Houdini:

• Mantra
• Mantra Principled Shader
• Mantra Triplanar Shader
• Arnold 
• Standard Surface
• Standard Triplanar

• Redshift
• Redshift Material
• Redshift Triplanar
• Renderman
• Pixar Surface
• Pixar Triplanar
• Octane 
• Universal Material
• Universal Triplanar

It also provides the following additional features to speed up your workflow:

• Atlas splitting
• Asset scattering
• LODs set up for 3D assets
• Apply motion to Plant assets
• Ability to import Megascans assets to USD stage if you work with Houdini Solaris and the following renderers
• Karma
• Arnold
• Renderman

Installation

Make sure Houdini is closed before installing the plugin.

1. Open Bridge, then from the Local filter in the left panel, go to the asset you want to export. You should see the Export Settings side panel below:
   
   
2. Set the “Export To” dropdown to “Houdini” and click on “Download Plugin”.

This should download the plugin, both to your library as well as install it inside Houdini.

In Houdini, Bridge will create a MegascansPlugin.json file at the following location (based on your OS) that references the plugin from your library:

• Windows: C:\Users\<Username>\Documents\houdini18.0\packages
• Mac OS: ~home/Library/Preferences/houdini/18.0/packages/MegascansPlugin.json
• Linux: Home/houdini18.x/packages OR Computer/home/<Username>/houdini18.x/packages

If you open this file it will have the path to where the Houdini plugin resides on your machine:

User Interface

When you launch Houdini you will see a new Megascans drop down menu in the Houdini menu bar.

Clicking “Megascans Plugin” from the dropdown will launch the plugin window. From here you can select the “Renderer” and “Material Type”.

Here’s how the different options on the plugin UI work:

• Renderer: Choose the renderer you’ve set up in Houdini.
• Material Type: Based on the selected renderer, this dropdown will show you the material setups you have available.
• Use Megascans Scattering: Check this box to enable scattering for your imported assets.
• Enable LODs: Check this box to set up LODs for 3D assets. When unchecked, only the LOD selected in the asset’s Export Settings is set up.
• Use Atlas Splitter: This will split up Megascans atlas assets when enabled.
• Apply Motion (Plants): When checked, this option will enable motion on Megascans plants.
• Import Assets on USD Stage: If you’re working in Solaris, enabling this option will let you import Megascans assets in USD format.

UI Preferences

The plugin’s UI preferences are saved in the Settings.json file at the following location:

<LibraryPath>\support\plugins\houdini\<PluginVersion>\MSLiveLink\scripts\python\MSPlugin

You can change the location of the file as follows:

1. Set up an environment variable called MS_HOUDINI_PATH.
2. Point the variable above, to the path where you want the Settings.json file to be at.

Exporting assets to Houdini

1. In Bridge, click on the asset you want to export in the Local filter and open its Export Settings:
   
   
2. Set the “Export To” to Houdini before you export. You can also tweak your export settings, like texture format, LODs, mesh format (FBX or OBJ), etc.
3. Click the “Export” button.

The asset should now appear inside Houdini. 

Always make sure that both Bridge and Houdini are running when exporting assets.

For specific renderers, upon export, textures are converted to formats that are optimized for use with those renderers. For instance:

• Mantra: .rat files will be created in the asset’s folder.
• Renderman: .tex files will be created in the asset’s folder.

Custom Installation

To do a custom install of the Magascans Houdini plugin, do the following:

1. Download the link from here, depending on your OS:

   WINDOWS   |   MAC   |   LINUX

2. Extract the MSLivelink folder to your desired location.
3. Go to the location where your houdini.env file exists. This by default is located here:
   

   Windows:	%HOME%/houdiniX.X/
   Mac:	~/Library/Preferences/houdini/X.X/
   Linux:	~/houdiniX.X/

4. In this location look for the packages folder.
   

   ❗Note: If the packages folder does not exist, create it.

5. Within the packages folder, create a file named MegascansPlugin.json.
6. Edit the file and enter the path of the MSLivelink folder you extracted in Step 2 as shown below:
   
   
7. In Bridge, on Export Settings, select Custom Socket Export.
8. Select the Use Socket Port option and set the port to 13290.