In this post we’re going to cover lighting options for best effect in your rendering within Revit as well as adding accent lights for an additional wow factor. In general you always want to ensure a hierarchy of lighting in your model. There should be a primary light, secondary light and a fill light with accent lighting used selectively. You do not want to over or under light your model. It should always complement materials and convey a sense of the space that sells your design.
Lights are important for varying the length of rendering time for a 3D image. You can place lights into your project (and vary their luminance while also changing time and date settings) but you should always remember the more lights you use the longer the rendering time. When an image is raytraced, you can accurately and clearly see the effects lights will have on the design.
Revits Default Lights in Shaded Views
When you shade a 3D view, Revit Building places default light sources aimed at the image; the default light source is called a headlight. These are not lights you can physically see and move; they are more for viewing purposes and preventing the model from appearing completely in black.
Creating a Light Fixture
The following is a general procedure for creating a light fixture. Steps may differ depending on your design intent. There are a number of different lighting family templates, including wall- and ceiling-based and spot and linear.
- From the File menu, choose New, Family.
- From the New dialog, navigate to the Templates directory and choose the Lighting Fixture.rft template. Revit Building opens the Family Editor with four views: floor plan, front and right elevation, and 3D.
- Sketch solid geometry for the light fixture. See topics on solid geometry creation.
- After sketching the geometry, click Family Types and specify a value for the Lumens property. For example, give your light fixture 5000 lumens. Click OK when finished applying values. A lumen indicates the amount light emitted from a light source. For incandescent lights, the ratio of lumens to watts is approximately 17 to 1. For fluorescent lights, the ratio is approximately 60 lumens to 1 watt. If you do not specify a value for lumens, Revit Building uses a default value of 1700 lumens, which is approximately equal to a 100-watt incandescent bulb.
- Save the fixture and exit the Family Editor.
You can also place light fixtures in a project by choosing the Load From Library, Load Family command from the File menu. After loading the fixture, click Component from the Basics tab of the Design Bar and select the fixture from the Type Selector. Place it in your project near the model. To see the effects of the light fixture on the model, raytrace the image. You can edit properties for a light fixture by selecting the fixture and clicking Properties.
Spotlights and Linear Lights
You can add spotlights and linear lights to your model in Revit Building. These lights are particularly effective when you render a 3D view.
Inserting a Spotlight or Linear Light
- Open a reflected ceiling plan view and create a ceiling.
- From the File menu, choose Load Family From Library.
- In the Open dialog, navigate to the Lighting Fixtures directory.
- Choose a family and click Open.
- Click the Rendering tab of the Design Bar and click Component.
- From the Type Selector, choose one of the light types you loaded.
- Place the light fixture in the desired location on the ceiling. Add as many lights as desired.
- Create a perspective view from a floor plan view. The perspective view opens automatically.
- Reactivate the Rendering tab of the Design Bar.
- If you are inserting lights for an interior scene, you can perform a radiosity solution first and then perform a raytrace.
- If you are inserting lights for an exterior scene, you can perform a raytrace.Creating a Spotlight with a Different Beam Angle
- Open the reflected ceiling plan.
- Select the light fixture and click Properties.
- Click Edit/New and click New to create a new type.
- Enter a name for the type and click OK.
- To make the beam more focused change the Spot Beam Angle to a lower value. This can make a bright spot on the floor smaller and brighter.
- To limit the spread of the spot light, lower the Spot Spread Angle value.
- To prevent any light from shining outside of a light cone, lower the Spot Tilt Angle. This will cause the spot light to shine off to the side. You could then rotate the light fixture to point it at a specific point.
- Click OK twice to finish the new lighting type.
- To control the brightness of any light, increase the Lumens value in the Type Properties of the light fixture. Change the Dimmer value in the Instance properties to make lights more or less bright. Dimmer values range from 0-2.0 where 1.0 is the normal strength of the light.Light Groups
You can group lights in a scene. You can create groups with all Revit Building light fixtures. You cannot create a group with the AccuRender sun.Creating the Light Group
- In a 3D view click Light Groups from the Rendering tab.
- In the Create Light Groups dialog, type a name for the light group and click OK. The new light group name appears on the Options Bar. You can rename the light group or delete it by clicking the appropriate command.
- Select lights in the view to add them to the group.
- Turning the Light Group on and off in the Scene
- From the Rendering tab, click Lighting.
- In the Scene Lighting dialog, select the light group name under the Mark/Name column.
- Select On to turn them on. Select On again to turn them off.
- Next to the On switch, set a value for Dimmer. The dimmer increases or decreases the brightness of the selected light group. Enter a value between 0 and 2.
- Click OK when done.
- Modifying Lights & Light Groups
In the Scene Lighting dialog, select a light group and click Modify selected lights. The dialog closes, and Revit Building enters a modify mode. You can choose different lighting types from the Type Selector. You can also click Properties to change common properties among the lights in the group.In the Scene Lighting dialog, select a light group and click Light Groups to begin modifying a particular light group. The dialog closes and you can change the grouping of the selected light group. Select the light group name from the drop-down menu on the Options Bar. Select lights in the scene to add them to or remove them from the group.Light Source Shape
More accurate lights require more render time. The Emit from Shape setting for a light source can impact render time. For example, point lights render faster than the other shapes. Line lights are slower. Rectangle and circle lights are slowest to render.
Revit uses area light sources to produce more realistic images. However, area shadows are expensive to compute. If you increase the quality of soft shadows, render time increases. (In the Render Quality Settings dialog, use the Soft Shadow options
Indirect illumination simulates the interaction of light with the environment by bouncing light off surfaces, including surfaces that are not directly exposed to a light source. If you increase the precision of indirect illumination and the number of bounces, you can improve the smaller, subtle effects of lighting, and the amount of light in a scene. However, increasing the amount of indirect illumination also increases the time required to render the image. (In the Render Quality Settings dialog, use the Indirect Illumination options.
Section Boxes & Light Groups
When you use section boxes to limit the geometry being rendered, you can significantly reduce the amount of time required to render an image. You can also use light groups to turn off lighting fixtures, thus reducing the number of lights that will impact the rendered image.. Remember, however, that lights that are not within the view can still have a significant impact on the quality of the rendered image.) Section boxes exclude lights that are clipped. When planned carefully and with forethought, the combined use of section boxes and light groups can greatly reduce the amount of time required to render an image.
So thats a comprehensive but quite general look at the lighting options in Revit but the options are endless and there are many tip and techniques you can employ which well cover in some other posts. For the moment experiment and enjoy.