--- title: "Intro to V-Ray for Nuke QuickStart" canonical: "https://documentation.chaos.com/space/VRAYNUKE/110625179/Intro%20to%20V-Ray%20for%20Nuke%20QuickStart" format: markdown --- This page provides an introductory QuickStart guide to using V-Ray for Nuke. ** ** ## **Overview** --- In this tutorial we are going to set up and render a simple scene using the V-Ray plugin for Nuke. This exciting new plugin gives you the ability to generate realistic reflections, refractions, subsurface scattering and image-based lighting directly in Nuke. First, we are going to create a simple comparison scene between the Nuke Scanline renderer and the V-Ray renderer inside of Nuke. Later on we will explore some materials and apply them to the geometry and look at how to add some V-Ray lights such as the VRay Light Dome. We'll then move on to adding some V-Ray render elements such as a MultiMatte, a Zdepth pass and a Specular, Reflection and Diffuse pass. We will then render this out to an EXR node and check out the render layers we have created. To follow this tutorial, you will need to have the V-Ray for Nuke plugin installed. This tutorial is a companion to go along with the QuickStart video posted on our YouTube channel. Want to follow along but don’t have a license? > Macro (ui-button) > Macro (iframe) ** ** ## **Tutorial Assets** --- To download the files used in this tutorial, please click on the button below. > Macro (refined-button) > ⚠️ Due to licensing issues, the Road_A.hdr file used in the tutorial video is not included in the downloadable assets. Instead, please use one of the provided HDR images in its place. ## **Tutorial Steps** --- ** 1) Set up comparison rendering** First, let's set up a comparison scene between the V-Ray Renderer node and the standard Nuke Scanline renderer so we can compare the two as we go through the techniques in this tutorial. To see the comparison, let's create a **CheckerBoard** and connect this to a **Card** with values set as shown in the image below. > Macro (inline-media-image) We bring in the geometry using the **ReadGeo** node and then add a Scene node named **Geom**. Connect the **Geom** node to the **Card** (to which the checkerboard is connected) and the **ReadGeo** node. To this we connect a Nuke **ScanlineRender** node and then add and connect the **Camera** node with the values shown. > Macro (inline-media-image) > Macro (inline-media-image) You should now be able to see a very simple Scanline renderer setup. To set up a V-Ray rendering for comparison we are going to keep everything the same, using the same values but simply connecting a **VRayRenderer** node to both the scene and the camera. In order to have a true ability to compare, we must change the VRayRenderer filter mode to Cubic (as shown) so that it matches the Scanline renderer. If you switch between the results of the Scanline render and the **VRayRenderer** node, you will see that V-Ray for Nuke gives far cleaner results. > Macro (inline-media-image) *Scanline render on the left; V-Ray render on the right* * * **2) Add a material** Let's add a little more complexity to the scene. Copy the existing **Scene** node, place the copy to the right of your current nodes, and connect it to both the **Card** node and the **ReadGeo** node. Also connect it to your **VRayRenderer** node. Let's add a V-Ray material to the scene by adding in the **VRayMtl** node. Connect this node to the checkerboard which will cause the checkerboard to act as a diffuse color texture. To have the material applied to geometry, we must create an **ApplyMaterial** node and connect it to the **VRayMtl** node and **ReadGeo** node. Also connect it to the new scene (which has been automatically named **Geom1**). ![image](media://6d7c582e-3b4a-4f21-8207-c7ccfcafc62f) If you take a look at the V-Ray rendering now, you'll notice that the geometry appears as completely black because there are no lights to illuminate the texture in the rendering. The Nuke Scanline renderer uses an ambient light, which is why you can see the texture in the Nuke rendering. * * **3) Add ambient light** We are going to add a V-Ray light ambient light to match the V-Ray rendering's lighting more closely to the Nuke Scanline rendering. Create a **VRayLightAmbient** node, and also a new scene named **Lights** so we can keep things well organized. Under the **Geom1** scene, create another scene named **Master Scene** and connect the scene named **Lights** to it. You'll now notice that the V-Ray rendering is lit, and you can see the texture. > Macro (inline-media-image) *V-Ray ambient light added to scene* **4) Add ambient occlusion** We are now going to take a look at some lighting techniques that can be used in your renderings in Nuke. ** ** **Ambient occlusion** is a shading and rendering technique used to calculate how exposed each point in a scene is to ambient light. In scenes with open sky this is done by estimating the amount of visible sky for each point, while in indoor environments only objects within a certain radius are taken into account and the walls are assumed to be the origin of the ambient light. The result is a diffuse, non-directional shading effect that casts no clear shadows but that darkens enclosed, occluded and sheltered areas and can affect the rendered image's overall tone. It is often used as a post-processing effect. We don't need the textures active on the geometry when making an ambient occlusion, so disconnect the **CheckerBoard** texture from both the **Card** node and the **VRayMtl** node. Add a **VRayLightDome** node, which will create a V-Ray light dome for us. Connect this to the **Lights** scene instead of to the **VRayLightAmbient** node. By default, the VRayLightDome is set to be the upper half of a white sphere that gives an even light and is also visible in the rendering. If you don't wish to have it in your rendering, check the **Invisible** checkbox under the **Options** section. When this option is checked, the light dome is still active and visible to the diffuse, specular and reflection colors but is invisible to the camera. The VRayLightDome can also be set to use a full sphere instead by checking the **Dome Spherical** checkbox under **Basic Parameters**. ![image](media://26c83cf2-4d3e-403d-ab97-23f428c53c16) *Ambient occlusion using a VRayLightDome with no textures, light dome set to visible to camera* > Macro (inline-media-image) *VRayLightDome set to be invisible to camera* **5) Add HDR texture** We can now add an HDR texture to light the scene by bringing the HDR into a **Read** node and connecting it to the **Tex** input of the VRayLightDome. This makes the HDR the texture for the VRayLightDome and allows us to have highly accurate lighting based on the HDR image. The HDR at this point is visible in the background the same way the light dome was when we used the same node for the ambient occlusion setup. So if, for example, we were using a plate that we were lighting to, we would again check the **Invisible** checkbox in the VRayLightDome. > Macro (inline-media-image) *HDR lighting using an HDR on the VRay Light Dome as a texture* Right now the white geometry looks rather flat and dull, so let's make it more reflective by going to the **VRayMtl** node and making some simple changes. With the **VRayMtl** node active, make sure you are on the **Reflection** tab and change the **Reflection Color** parameter to a value of 1. Now you have a wonderful reflective material, and that both the HDR and the ground geometry are visible in your reflections. > Macro (inline-media-image) *A reflective VRay material assigned to the geometry* **6) Assign multiple materials** Let's change the material assignments for the geometry so we can make things a little more interesting. With your **AssignMaterial** node active, you will see a dropdown box named **Filter**. We can make use of this option to assign different materials to different parts of the model. To start the process, create a **VRayProxy** node and load in the model. The **VRayProxy** node can load in VRMesh and Alembic files. It also gives us a lower resolution version of the model for ease of use in the display while the full high-resolution version is used at render time. Connect the **VRayProxy** node directly to the **ApplyMaterial** node. If you go back to the **ApplyMaterial** node, you can assign the materials by clicking on the Filter dropbox, then clicking **Name** and **Choose**. > Macro (inline-media-image) *Swapping the ReadGeo node for a VRayProxy node* You will see a window pop up with the geometry objects in the scene that have names assigned to them (these names were assigned prior to use in Nuke). To apply the reflective material we've just set up to just the sphere part of the model, select **Sphere**. The other parts of the model no longer have the reflective material on them as we have specifically told Nuke that we only want that material on the sphere part itself. > Macro (inline-media-image) *Assigning the reflective material to just the sphere part of the model* The base material is currently assigned to everything that we haven't specifically told Nuke to apply the reflective material to. To make a new material for the base color, create another **VRayMtl** node. To keep things organized, name the first **VRayMtl** node we created (the reflective shiny one) to **VRayMtlReflective**, and the second **VRayMtl** node **VRayRed**. Change the **Diffuse Color** of **VRayRed** to a red color with a value of 0.5, 0, 0, 0.5. > Macro (inline-media-image) *Making and assigning the red V-Ray material* Add an **ApplyMaterial** node just below the **VRayProxy** node and connect the **VRayRed** node to this. Just as we did before, we go to the **Filter** dropdown box, choose **Name**, then click the **Choose** button, only this time we pick the non-sphere parts. ![image](media://ea087951-f6f3-4fc1-bcab-b59959e7885c) Then add in a **VRayMtlWrapper** node just below the **VRayRed** node. In the **Material ID** section of the **VRayMtlWrapper** node's parameters, set the **Multimatte ID** to a value of **1**. This allows us the ability to isolate and control these areas. Rename the **VRayRenderElement** node (not the scene) to **Multi_Matte** to save any confusion later. > Macro (inline-media-image) *Red Multimatte setup* **7) Set up render elements** Let's set up some V-Ray render elements for the render. Create a **VRayRenderElement** node and then create a new scene and name this **VRayRenderElements**. With the **VRayRenderElements** scene active, click on the **Render Elements** dropdown box and set it to **MultiMatte**, and set the value of the red object ID to **1**. Also check the **Use Material IDs** checkbox. Then connect the **VRayRenderElements** scene to the **Master Scene**. When you look at your rendering in the viewer, you should see a **Multi_Matte** option with the protruding parts as a solid red color. Let's set up another multi matte for the sphere part itself, but using a different color. Create another **VRayMtlWrapper** under the **VRayMtlMirror** node (which contains the reflective shiny material) and set the **Multimatte ID** parameter to **2**. We then go back to the **Multi_Matte** node and set the value for the blue channel to **1** as well. In your viewer, when Multi_Matte is active, you will see the sphere itself as blue and the protruding parts as red. * * **8) Set up rectangular light** Let's explore another light, the V-Ray rectangular light. Create a **VRayLightRect** and connect it to the **Lights** scene. You can control this light via a large number of parameters, but for now let's just start by changing the **U size** and **V size** to 500 each. You can then interactively change the position and angle in your Nuke scene to place it exactly where you want or need the light source to be. This light source gives you shadows, and it is also visible in the reflections and in renderings unless you check the **Invisible** checkbox under the light's **Options** section. > Macro (inline-media-image) *V-Ray rectangular light* If we want a more of a studio lighting setup, we can disconnect the HDR from the **VRayLightDome** texture (and maybe even make this once again invisible). You could even disconnect the light dome and see just the contribution of the **VRayLightRect** when used on its own. * * **9) Prepare for render elements** Now that we've gone over the basics of setting up a V-Ray for Nuke scene, we can move on to rendering elements that can be used in post-production. Connect the **VRayLightDome** back up, and add a few more **VRayRenderElements**. Remember that each one will need to be connected to the **VRayRenderElements** scene. **10) Set up Zdepth element** Let's start with a **Zdepth** element. Set the first **VRayRenderElement** to a **Render Element** of **Zdepth** and rename it **ZDepth**. Set the **Depth White** to **1** and the **Depth Black** to **0**, and make sure the **Depth Clamp** checkbox is unchecked. This provides a true depth from camera. Don't worry if the depth image appears to be mainly a single color, as this is a floating point. By hovering over the pixels, you will see the actual values change. You can view the Zdepth render pass by changing to it in your viewer. > Macro (inline-media-image) *Zdepth pass and settings* **11) Set up Specular, Reflection and Diffuse elements** Creating the Specular, Reflection, and Diffuse **VRayRenderElements** is easy and the parameters that can be changed are minimal. These are fairly traditional and commonly used passes. Name each one accordingly and connect them to the **VRayRenderElements** scene the same as you did with Zdepth. Rename **Multi_Matte** node to **SphereMatte** to keep things well organized while we progress. Keeping your Nuke scripts well organized also means that it is easier for anther artist to pick up a script in production and be able to make sense of it. Add a **Write** node to your scene and set it as shown in the image to render as an OpenEXR, making sure the **Channels** are set to **All**. This will add all the channels to the EXR so they can be accessed from a single image file. Click **Render** to render the image to the location specified. If you bring back the image you've just rendered into a **Read** node, you will be able to view each of the channels via the dropdown above the viewer. You should see the following list of layers: Rgb Rgba Diffuse Reflection Specular Sphere_matte Zdepth Congratulations! You've just set up a simple scene with V-Ray for Nuke, with render elements that can be used for further post-processing. > Macro (inline-media-image)