Houdini – Rendering with V-Ray – first steps

Software:
Houdini 18.0.460 | V-Ray Next 4.30.03

This post covers the most basic steps needed for rendering with V-Ray Next for Houdini.

Note on software versions:
At the moment of writing this post V-Ray for Houdini supports Houdini version 18.0.460.
I naively thought it would work with a later version of Houdini, I tried to install it on Houdini 18.0.499 thinking to myself “what can a couple of extra numbers do..” but I was wrong, It crushed. so at the moment it has to be Houdini 18.0.460, so when getting started with this, take a moment to see exactly what Houdini build is the installation of V-ray built for and install that specific version of Houdini.
* It’s easy, the V-Ray Installation package’s name states the version:
“vray_adv_43003_houdini18.0.460.exe”
Full installation instructions on the V-Ray for Houdini documentation:
https://docs.chaosgroup.com/display/VRAYHOUDINI/Setup+and+Installation

Adding the V-Ray tool shelve to the Houdini UI:
Click the “+” button at the right of the available shelves, and from the list, select V-Ray.
* This only has to be done once.

Scene preparation note:
Surface objects have to be of type Polygon, Polygon Mesh or Polygon Soup for V-Ray rendering:

Setting up V-Ray rendering:
There are 3 ways to setup V-Ray as a render output option for your scene:

  1. In the out network, add a V-Ray > V-Ray Renderer node.
  2. In the main menu, Select Render > Create Render Node > V-Ray.
  3. In the V-Ray shelf, click the Show VFB button.
    This will open the V-Ray VFB (render window), and create both V-Ray Renderer and V-Ray IPR nodes in the out network.

* A V-Ray IPR node is needed for interactive rendering both in the Houdini view-port Region Render and in the V-Ray VFB.

Creating a camera:
You guessed it.. 3 ways to create a camera:

  1. Open the camera drop-down menu found at the top right of the view-port, and select New Camera.
    A new Camera node will be created and the view-port will be set to display the new camera view.
  2. In the Lights and Cameras shelf. press the Camera button, and click inside the 3D view-port to create a new Camera node.
  3. Create a Camera node directly in the obj network by right clicking and selecting Render > Camera.

Note that the rendered image resolution is set in the Camera node’s View properties:

Adding V-Ray Physical Camera properties to the Camera:
With the Camera node selected, press the Physical Camera button in the V-Ray shelf.
This will add a new V-Ray tab to the Camera node’s properties, containing V-Ray Physical Camera properties.
Note, that the Physical Camera exposure settings are setup by default for physical sunlight illumination levels (EV 14), so in many cases, after adding the Physical Camera properties, unless these settings are tuned, your scene will render darker.

Adding light sources:
To add light sources, In the V-Ray shelf, press the wanted light source button, click the 3D view-port to create the light node, transform it to the wanted location/orientation, and set it’s settings:

* If no light sources are added, The image will be rendered using default lighting.

Setting up V-Ray materials:
In the mat network, right click and select V-Ray > Material > V-Ray Material to create a V-Ray Material node:

Select the V-Ray Material node, name it, and set it’s material settings:

In the obj network, double-click the wanted geometry object to enter its SOP network, and inside its SOP. create a new Material node:

Connect the sphere primitive SOP node’s output to the new Material node’s input, make sure it is displayed by clicking the right most node button so it’s highlighted in blue.

In the Material node’s properties, open the Floating Operator Chooser next to the Material property, to select a material for the surface, and in the hierarchical display, expend the mat network, and select the wanted V-Ray Material:

Now that a material has been set and the Material node is displayed, the objects is rendered with the selected material:

Rendering an image:
There are 3 ways to render an image:

  1. In the main menu, select Render > Render > vray
  2. In the out network, click the V-Ray renderer node’s Render button (on its right), to open the Render dialog, and in the dialog press Render.
  3. In the V-Ray shelf, press the Show VFB button to open the FVB (V-Ray’s render window), and there, press the Teapot button at the top right to render the image.

UE4 – “Cleaning up” the FPS template for an Archviz project

Software:
Unreal Engine 4.25

Annotation 2020-06-18 194857

The UE4 First Person template is a good way to start an Architectural virtual tour project, but we first need to “clean” it up, namely, get rid of all the unnecessary objects and settings.

Start with the obvious:
Delete all the cubes and blocks. (Simply select them and press delete)
The quickest way to select all these objects is through the World Outliner window.
Select all the unneeded objects (see image below) and delete them.
Note:
I’m intentionally keeping the 4 surrounding wall objects because I want them to serve as invisible barrier objects that will stop the player from wondering of the platform.Annotation 2020-06-18 195553

So now our level looks like this, with weird static shadows left by the “BigWall” objects that were deleted.
It’s not really critical to fix this at this stage, but if you want to get rid of the weird left-over shadows, simply press the Build button to re-build the lighting, and they will be gone.Annotation 2020-06-18 200303

Making the walls invisible:
Select the 4 wall objects, and in the Details window, in the Lighting Settings uncheck Cast Shadow,
And under Rendering uncheck Visible.
The level is now clear, and when we press play, we can free roam on the empty stage until we hit the invisible walls.
* You can re-build the lighting to get rid of the walls static shadow.
Annotation 2020-06-18 203043

Time to get dirty!
We now have to get rid if the FPS rifle and shooting setup….
Select the FirstPersonCharacter actor, and in the World Outliner window click Edit FirstPersonCharacter to open the actors Blueprint:
Annotation 2020-06-18 210611
In the FirstPersonCharacter Blueprint, navigate to the Viewport tab so you’l be able to see the mesh components clearly,
And in the actor Components Window on the left, select all the unneeded components, delete them and press the Compile button.
* make sure you don’t select the FirstPersonCamera or any of the inherited componentsAnnotation 2020-06-18 211326
A list of reported errors will now be displayed in the Compile Results window, because we deleted objects that are referenced by the Blueprint, we will fix this in the next step:Annotation 2020-06-18 211509
Navigate to the Construction Script tab, Select the AttachComponentToComponent node (currently displaying an error) and delete it.Annotation 2020-06-18 213100
Navigate to the Event Graph tab, locate the first Event Graph at the top of the Blueprint, this is the Event BeginPlay graph.
Select the 2 Set Hidden in Game nodes (currently displaying an errors) and delete them:Annotation 2020-06-18 213152
Locate the Spawn projectile node graph at the bottom of the Event Graph,
Select this whole section, delete it and press Compile.
Annotation 2020-06-18 213243
The Event Graph should now look like this, and compilation should be without errors because we deleted all the Blueprint parts that were referencing the deleted actor components:Annotation 2020-06-18 213349

Almost there..
It’s time to remove the small red targeting cross-hair icon displayed on the screen when playing.
The cross-hair icon is defined in the level’s HUD (Heads Up Display) Blueprint class.
The easiest way to remove it is to simply remove the HUD class from the level.

Note:
The FirstPersonHUD class can be useful to an Archviz project for displaying branding and architectural data on screen so it’s good to keep it in the project. it can later be modified to suit our needs used again (doing that is beyond the scope of this article).
If you wish to edit the HUD Blueprint instead of disconnecting it from the level, you’ll find it in Content > FirstPersonBP > Blueprints > FirstPersonHUD:
Annotation 2020-06-18 220637

To remove the HUD from the level, navigate to the World Settings window,
If it isn’t displayed open it from Settings > World Settings:
Annotation 2020-06-18 220538
In the World Settings window, under Game Mode > Selected GameMode, open the HUD Class drop-down and instead of FirstPersonHUD, choose None.
This will remove the HUD from the level but wont delete it from the project:
Annotation 2020-06-18 220513

Were done!

You can now decide whether to keep the default daylight setup or maybe delete its actors and create an HDRI lighting instead,
And you can now import your Archviz scene via the Datasmith plugin.

Hope you found this article useful! 🙂

Related posts:

  1. 3ds max & V-Ray to UE4 Data Smith workflow
  2. UE4 HDRI lighting
  3. UE4 – Connecting the directional light to the atmosphere
  4. UE4 Architectural glazing material
  5. UE4 – Archviz Light calculaion tips