This page provides a step-by-step introduction to Lighting in V-Ray for Revit.


Page Contents

 

Introduction


This tutorial covers lighting techniques for interior spaces. We will light and render this project using artificial lights as well as the environment sun light.

To follow this tutorial, you will need to have the V-Ray for Revit plugin installed. This tutorial is a companion to go along with the QuickStart video posted on our YouTube channel and is available here:

 

 

 

 

Tutorial Assets


To download the files used in this tutorial, please click on the button below.



Tutorial Steps


Open an Example Scene

Open up the project file “interior_lighting.rvt" which can be downloaded from the Tutorial Assets section above. If you are using a version of Revit newer than 2015, Revit will automatically update the model in a few seconds. Here we will be using Revit 2017. This scene is a basic interior with some simple furniture, windows, and interior lights. 


 

 

Run a Test Render Using V-Ray RT

We’ll start with setting up a simple environment light using the V-Ray Sun/Sky system.

To get your scene ready to for V-Ray RT, go to the V-Ray tab and set the current view to the Render view. Keep Quality at Draft. Leave the Resolution at 800 x 600, or adjust it to be smaller if you have a slower machine. Leave Artificial Lights off. By default, the Sun is already enabled and ready to go.

 

 

Start a Render with V-Ray RT from the V-Ray tab. 

 

 

Replacing the Self-Illuminating materials

You’ll notice some of these lights appear to be on despite our turning off artificial lights.These are actually self-illuminating V-Ray materials and not standard Revit lights. These materials are made to act like light sources, and we’ll cover them later in this tutorial.

Since this Revit Family has already been set up with this material, we'll switch that material to a disabled version so we can focus on illumination coming from the sky system.

 

Click Stop in the Progress window to halt the render.

 

 

 

Click on the lamp in the scene and then click on Edit Type in the Properties window to replace the lamp’s material.

 

 

 

Select the Shade option under Materials and Finishes.

 

 

 

In the material browser, select the material Lamp Glass – Disabled. This material is included with the project and is the lamp material with the self-illumination disabled. Click OK to complete this operation.

 

 


Restart the RT render and you’ll see those materials are no longer self-illuminating.

 

 

 

Changing the angle of the sun using Time and Date

The RT render shows that the sun is not lighting the room very well yet. Let's move the sun so that the room is cast in light. We can use the time and date to use real-world sun positioning. Keep V-Ray RT running to see your changes live.

To gain access to the Sun settings, Activate the Render view, and click on the Rendering Settings button in the properties.

 

 

 

Click on Sun Settings button and here you can adjust the sun to suit our needs.

 

 

 

Change the Date to June and click Apply. 

If you receive a Revit error when attempting to modify these parameters, open and close the Dynamo plugin from the Manage tab.

 

 

 

The RT Render shows how the sun is creeping onto the porch a little bit now.

 

 

 

Now change the time to 6:30pm and hit Apply.

 

 

 

You’ll see the sun is coming into the space and gives a nice sunset look to the room. How nice!

 

 

 

Changing the angle of the sun using Azimuth and Altitude

To further find an angle we'd like, we can use Azimuth and Altitude to dial in an exact angle of sunlight into the scene.

Change the Solar Study from Still to Lighting for different types of controls on the sun. Click apply so we can see the change.

 

 

 



The new settings are based on azimuth and altitude to define the position and angle to the horizon of the sun. You can change these settings to see how the sun position changes the lighting.

Change Azimuth to 292 to get that sunlight right into the space. Play around with the Altitude a little bit to see how that affects the room. Setting the angle to a lower number like 15 gives you a nice sun set or sun rise look.

 



 

 

You'll see that changing the Altitude changes the color of the sky and the sun along with the angle of light. Click Ok in both dialog windows.

 

Softening the Sun's shadows

Click on the V-Ray Sun button in the V-Ray Tab to access the settings. Change the Sun Size from the default of 2, which is generally the most accurate setting, to 6 to make the shadows get much softer. The higher you go the softer the shadows will get, which may not be physically accurate, but might be a nice effect.

 

 

 

 

 

Using an HDRI map to light the Scene

As an alternative to lighting with the V-Ray Sun System, the scene can be lit using an High Dynamic Range Image (HDRI.) Let’s switch from the Sun to a Dome light in the V-Ray Tab. This will replace the Sun lighting system with a Dome Light source.

 

 

 

RT updates to show the dome lighting evenly as a solid color, almost like a heavy cloudy look outside.

 

 

 

In the Dome light Settings window, enable Use HDR Image. V-Ray for Revit Includes a HDR image by default, but you can use your own HDR file you like. We’ll use the default one for this tutorial.

 

 

 



You can play with the rotation setting to change the position of the sun in our dome to change the lighting in the room.

Let’s move the sun to 22 degrees to get the sun beating into the room again.

 


 

Artificial lights

Go ahead and Stop the RT render for now. lets focus on the artificial lights in the room. Turn on Artificial Lights.  Switch to No Light in the environment lights to disable the dome light for the time being. 

 

 

 

Setting up Self-Illuminated materials

First, we’ll add the self-illuminated materials back to the lamps. Select the lamp, click Edit Type, and on Shade to get back to the material selection.

Select the Lamp Glass material as we had before. This is an emissive material, which will light the scene from the surface of the lamp. Click OK.

 

 

 

Lets check how that looks by restarting the V-Ray RT render from the V-Ray Tab.

 

 


The lamp shades are illuminating the scene, but it’s rather dim and moody. Lets change that by increasing the exposure of our camera.

Click on the Camera Settings icon and adjust the Exposure (EV) slider to Bright Interior with a value of about 8. The scene should brighten up quite nicely.

 


 

 

Tuning the Artificial lights

Lets check out a production render to see how the artificial lights are handling.

Stop the RT render. Click the Render V-Ray RT’s pulldown arrow, and select Render with V-Ray.

 

 

 




Click Stop when you’re happy with a draft quality. We can see that those wall fixtures don’t appear to be on or doing much lighting. V-Ray for Revit looks at the settings in the Revit Families to get their parameters when it lights the scene, so maybe these lights in the scene aren’t bright enough.

Click on the wall light in the viewport, and then click Edit Type in the properties. Scroll down and you can see the initial intensity is only 10 lumens, which is not at all bright. Click it and change it to 180 lumens and click OK.

 

 

 

Lets take a look at how that changed the light. Instead of re-rendering the whole scene Since this will mostly effect only a small portion of the space, let’s just render this region by clicking the region render button in the VFB.

 

 

 

Click and drag a box around this light.

 

 

 

Go back to the V-Ray tab and click Render and it will update just that region. There’s our light!

 

 

 

Disable Cast Shadows from the Emissive Lampshade Material

The Lamp's Emissive materials light the room as well, which makes them look as if they’re turned on. However, as you can see it’s a different color than the rest of the light in the room. Lets change that and refine the way light falls off of it while we're at it.

Inside the lamp is an artificial light. Emissive materials, by default, don’t allow other lights to go through them. The warm light we have inside this lamp is only coming out of the top and bottom of the openings in lamp shade as you can see by the falloff pattern on the wall. The cooler colored light on the wall is coming directly from the emissive material itself and not from the light inside the lamp.

We can allow that light to pass through by using a V-Ray material.

Go to the V-Ray Material Browser, and type in the word “lamp” to find it. You’ll see “Lamp Glass” as one of the materials. Click the drop down AutoGen and replace that with VRayMaterial.

 

 

That opens a file browser. Navigate to the emitter_material.vrmat material that comes with the tutorial assets.


Select a render region around the lamp in the V-Ray Frame Buffer (VFB), and click Render to see the changes

 

 

 

The render only changes slightly, it’s still only using the self-illumination from the material here on the wall. To let the light pass through the lamp shade, Click on the Edit V-Ray Material button in the V-Ray Material Browser.

 

 

 

Select the Advanced tab and open the Options rollout. Disable Cast Shadows to enable the light Revit light inside the lamp to go allow light to go through the lamp shade.

 

 

 

Click on File menu in the VRMat Editor and Save the changes to the material. Go ahead and close the Material Browser.

 

 

 

Now re-render that region and you’ll see that the light inside is coming through the lamp shade and lighting the wall along with the self-illumination from the shade’s emissive material itself.

 

 

 

 

Disabling the Emissive Properties of the Lamp Shade.

While this looks good, the light is not physically accurate because the emissive material on the lamp shade is contributing extra light along with the artificial light. That’s easy to address by changing the lamp shader’s material to be more like a real frosted glass as opposed to an emissive material.

In the Material Browser, click on the Lamp Glass material drop down to set it back to AutoGen and close the browser.

 

 

 

Select the lamp object and click on Edit Type in the properties. In the Type Properties window, click on the Shade’s Lamp Glass material for the Material Browser window.

 

 

 

Here we'll disable that emmisive element of the lamp shade. Click on the Appearance tab and disable the Self-Illumination check box, and click OK to close out those windows.

 

 

 

Render again to see the change which creates a more predictable, accurate result for the light in the lamp with a frosted glass shade.

 

 

 

Combining the Artificial Lights with the Environmental Lights

Let’s get those artificial lights to work alongside the environment lights.

Turn off the Region Render in the VFB and start an RT render again to get a benchmark of the current scene.

 

 

 

Select the Dome light under Lighting on the V-Ray Tab to turn it back on. RT updates and shows us this is way too bright.

 

 


One way to match the light sources, which is not physically accurate but quick and effective, is to reduce the Intensity of the Dome light.

In the Light Dome Settings, set the Intensity to 0.025 and the environment light will be much less bright overall to create a night scene. The same thing can be done when using the V-Ray Sun.

 

 

 

Setting the Intensity down even further will give us a night render with some environment light from outside.

 

 

 
Stop the RT render. Change the Quality to High and set the Resolution to 1152x864 for a bigger, nicer render.

 

 

 

Click Render with V-Ray to start the final rendering. The longer you allow it to render, the cleaner the result will be. Stop the Render when you're happy with the result.