Rendering Tutorials >
Creating a Shadow Study

You can animate a Daylight system's time of day. This is a good way to create a shadow study.

In this tutorial, you will learn how to:

- Use a Daylight system to create animated shadows.
- Use viewport shadow settings to investigate the shadows cast by the buildings in a single city block.
- Use mr Sky (mental ray Sky) to provide sky color.
- Render selected frames for later inspection or presentation.

ImportantThis tutorial demonstrates hardware shading. In order to see hardware-shaded shadows and other effects, your graphics hardware must support Shader Model 3.0 (SM3.0) or a later version.

If you aren’t sure what graphics hardware you have, in 3ds Max Design choose Help Diagnose Video Hardware. This displays a dialog with details about your graphics configuration, including GPU Model Shader Support, which shows the Shader Model version number.

If your graphics hardware doesn’t support SM3.0, or you are using the Software driver rather than OpenGL or Direct3D, you can skip this tutorial. Or you can do the first procedure, where you animate the daylight, then skip to the last procedure, which uses the mental ray renderer.

Skill level: Beginner

Time to complete: 30 minutes

Preparation for This Tutorial

- If you have not already downloaded the tutorial files (MAX scenes and other assets), download them now and unzip them into a project folder called \Autodesk 3ds Max Design 2012 tutorials. See Where to Find Tutorial Files.
- On the Quick Access toolbar, click (Project Folder) and set your current project to Autodesk 3ds Max Design 2012 Tutorials.

Set up the scene:

- On the Quick Access toolbar, click (Open File), navigate to the \scenes\rendering\cityscape folder, and open cityscape.max.
  NoteIf a dialog asks whether you want to use the scene’s Gamma And LUT settings, accept the scene Gamma settings, and click OK. If a dialog asks whether to use the scene’s units, accept the scene units, and click OK.

  The scene consists of a city block, with a skyscraper at the center. The scene also contains a Daylight system. The system is set to position the scene at the latitude of San Francisco, California, with sun position set at 0700 hours, about the time of dawn on a winter day.

  Tip Lighting and Rendering the Villa in Daylight takes you through the steps of creating a Daylight system.

Animate the daylight:

1. On the main toolbar, turn on (Select Object).
2. In the Top viewport, click the sun object to select it.

   Daylight01 appears in the name field on the command panel.

3. Go to the Motion panel.
4. Turn on (Auto Key).

   The button, the track bar, and the border of the active viewport all turn red.

5. Drag the time slider to frame 60 (or click (Go To End)), and then on the Control Parameters rollout, change the Hours value to 19.

   The spinner arrows of the Hours, Minutes, and Seconds fields are now bracketed in red, indicating that you have set a key to animate the time of day.

   When you use Auto Key to set a key at frame 60, 3ds Max Design also sets a key at the start frame, frame 0. So the sun is now animated to range from 0700 to 1900 hours, or 7 A.M. to 7 P.M. Because there are 61 frames in the animation, the sun reaches the top of the hour every five frames.

6. Turn off (Auto Key).
7. Drag the time slider.

   You can see the movement of the sun.

8. Click (Go To Start) to return to frame 0.

Use viewport lighting to view the scene:

1. Activate the Camera02 viewport, and maximize it.
2. Click the Shading viewport label menu (the one that now reads “[ Smooth + Highlights ]”), and choose Lighting And Shadows Illuminate With Scene Lights.

   Now the scene is illuminated by the mr Sun light that is part of the daylight system, and the Camera02 viewport shows the lighting early on a winter morning.

3. Click the Shading viewport label again, and choose Lighting And Shadows Enable Hardware Shading.

   With hardware shading, the scene is considerably darker, which is probably more realistic for this time of year. In any case, hardware shading allows you to see shadows in the viewports.

4. Click the Shading viewport label menu again, and choose Lighting And Shadows Enable Shadows.

   At 0700 hours, there is no visible change in the viewport.

5. Drag the time slider.

   As the sun progresses across the sky, shadows in the viewport move across the cityscape.

   0900h

   1200h

   1500h

Reduce the shadow density:

1. Drag the time slider to frame 40 (1500 hours).
2. Click the Shading viewport label menu, and choose Lighting And Shadows Configure.

   3ds Max Design opens the Viewport Configuration dialog, opened to the Lighting And Shadows panel.

3. In the Viewport Shadows And Ambient Occlusion group. change the value of Viewport Shadow Intensity to 0.8, then click OK.

   Now the shadows have a density of 80 percent, and look somewhat softer.

   Reducing shadow intensity can be a pleasant effect. It can also be more realistic for a site such as this, in San Francisco, where there is often cloud cover and the lighting is more diffuse than direct sunlight.

   NoteWith hardware shading, you also have the option of generating soft-edged shadows. These can improve the realism of a display, but in general, they aren’t as useful for shadow studies.

   Next, you will improve shadow quality by adding Ambient Occlusion.

Add Ambient Occlusion:

Ambient Occlusion (AO) is a technique for improving the appearance and density of shadows. Rather than tracing light rays, it takes into account the proximity of objects in the scene.

1. Click the Shading viewport label menu, and choose Lighting And Shadows Enable Ambient Occlusion.

   3ds Max Design updates the viewport shadows.

   With Ambient Occlusion, shadows are denser and have more detail.

2. Click the Shading viewport label menu, and choose Lighting And Shadows Configure.
3. On the Viewport Configuration dialog, change the Ambient Occlustion quality slider from Medium to High. Click OK.

   The difference is subtle, but there is an improvement.

View the effects of mr Sky:

One advantage of using mr Sky as the sky light for the Daylight system, is that this light changes color depending on the time of day.

The angle of Camera02 is too high to get a good view of the sky, so first you change views.

1. Click the Point-Of-View (POV) viewport label (which currently reads “[ Camera02 ]”), and choose Cameras Camera01.

   This is a more oblique view of the city block.

2. Click the Shading viewport label menu, and choose Viewport Background Show Background.

   3ds Max Design shows the sky and horizon. The sky is colored according to the time of day.

   0900h

   1200h

   1500h

   1648h

Save your work:

- From the Application menu, choose Save As. In the file dialog, name the file my_shadows.max, then click Save.
  TipAlways save your scene file before you render.

(Optional.) Render snapshots of the shadow study:

A hardware-shaded viewport is great for interactive display. But hardware shading doesn’t include the full detail of a rendering. Also, sometimes hardware shading generates artifacts, as you can see in the previous graphic of the viewport with noontime lighting. For further study, or to make a presentation, you might want to render the shadows.

You can turn the shadow study into an animation, but for this tutorial, you will render only selected frames.

At 0700 hours, when the animation begins, and 1900 hours, when it ends, the scene is too dark to be interesting. So you will render selected frames from a smaller range.

1. On the main toolbar, click (Render Setup).

   3ds Max Design opens the Render Setup dialog. The Common panel is active.

2. In the Common Parameters rollout Time Output group, set the range from frame 5 to frame 45 (0800 to 1600 hours). Also set Every Nth Frame to 5.

   You will render nine snapshot frames over the course of the main daylight hours.

3. In the Output Size group, click the 800 x 600 button.

   Smaller sizes render more quickly, but the shadows don't show up as well.

4. Scroll down to the Render Output group. Click the Files button.

   3ds Max Design opens a Render Output File dialog. By default, 3ds Max Design saves renderings in the \renderoutput folder for the tutorials. You can change this location if you like.

   Choose JPEG as the output type, and enter thirdstreetblock as the file name, then click Save.

   Accept the defaults for the JPEG file format.

   TipEven when you create an animation, rendering to sequentially numbered still image frames can be a good idea. If you need to correct mistakes, you can correct individual frames without having to re-render the entire animation.
5. Make sure Camera01 is the active viewport, then click Render.

   3ds Max Design renders the individual frames. Each frame has the file name you entered, followed by a sequence number that equals the frame number.

   Fully rendered frame from the snapshot set

   You might want to experiment. For example, changing the Daylight system’s month to a month in summer will show more hours of daylight, and shadows that have a different orientation.

   A completed version of this scene is saved as cityscape_animated.max.

Save your work:

- Save the scene as my_cityscape_shadows.max.

Summary

To create a shadow study you can use Auto Key to animate a Daylight system’s time of day. With hardware viewport shading, you can view shadows. Turning on Ambient Occlusion improves the shadow quality. The sky light mr Sky provides sky color. You can also use the renderer to create fully detailed frames, or an animation.