CAP 201a - Computer Animation I
Lesson 8 - Chapter 11, 3DS Max Rendering
This lesson discusses rendering 3DS Max scenes, and 3DS Max cameras. Objectives important
to this lesson:
- Rendering setup
- Motion blur
- Active Shade
- Render elements
- Rendering effects
- Raytraced reflections and refractions
- Rendering the rocket
The chapter begins with a discussion of the importance of rendering. Rendering was listed back in chapter 1 as the first step in post-production. It could be argued that rendering is production, as far as the final product is concerned.
The text continues with parameters for rendering. If you do not already know how to open the Render Scene dialog box, you are given three ways: Click the Render Scene icon in the toolbar, select Rendering, Render from the menus, or press F10.
This dialog box is broken into five tabs, each of which has sections that affect any render, including a quick render. On the Common tab, Common Parameters rollout, several features are defined:
- Time output - default setting is a Single frame, but you can select the Active Time Segment (all frames of the scene), a Range of frames, or a list of specific frame numbers. The last two are more useful for rendering a portion of a scene. The Every Nth Frame option lets you make a test render of a series of frames, to check whether you need to change any settings. It can alert you to lighting, rigging, and animation mistakes before you spend the time rendering the entire scene.
- Output size - Settings for the resolution of the output, including preset resolutions on buttons that can be redefined by the user.
- Options - This is a series of toggles, that tell the render engine to consider or ignore specific features of the scene. Some of the options:
- Atmospherics - Render or ignore atmospheric effects
- Effects - Render or ignore other kinds of effects
- Displacement - Render or ignore surface displacement from maps
- Video Color Check - checks for colors that are not safe for NTSC or PAL formats
- Render Hidden Geometry - Render or ignore objects hidden in the selected view
- Force 2-Sided - Render or ignore the inside of objects; necessary for an accurate render if the inside of an object is visible
- Render Output - You use this to save your render as a file. You specify the type of file, the location to store the file, the name of the file, and the codec to use (if you are rendering an animation). You should be aware of the various output formats that are options.
Question 1: List three animation file output formats mentioned in the text. List a venue in which each might be used. (Check the Internet for this information.)
The E-mail Notifications rollout hints at a problem we have not had yet. The problem is that a render might take a long time. This rollout gives you a way to send an e-mail message on completion, provided you have an SMTP server to send the message through.
The Assign Renderer rollout gives you a place to change the renderer used by various parts of 3DS Max. You should do so when you need to, but remember what you have done. It will not help to change the ActiveShade renderer (to see previews of renders), and not the Production renderer, if what you are trying to see is a true preview of what the output file will look like.
3DS Max comes with two render engines built in: the default scanline renderer and the mental ray renderer. You have used the scanline renderer in all the quick renders done in this class. The text mentions that it renders a series of horizontal lines. If you watch the render window when this is going on, you can easily see the lines being drawn.
The mental ray renderer produces more careful rendering of light that is reflected or refracted in your scene. The author describes mental ray as the more powerful renderer. You should be aware that you can buy other rendering engines to install as plug-ins for 3DS Max, which have more capabilities as well.
Chapter Exercise 1: Rendering the bouncing ball
This exercise starts on page 508.
- Open the file specified in the text.
- Open the Render Scene dialog by one of the methods mentioned above. In the Time Output section, click the radio button for Active Time Segment. (This means all frames on the timeline.)
- Find the Output Size section and click the button for 320x240.
- Find the Render Output section and click the Files button. (It is the only thing you can do in that section at the moment.) This takes you to a window where you will do several things:
- Navigate to the folder where you will save your output (This is more important than it sounds. You need space to write a video file, and you need to know where you put it.)
- Enter a filename for your output file.
- Click the Save As Type dropdown, and choose MOV Quick Time File.
Question 2: Assume you are going to distribute this file on a web site. What does using this file type for output assume about your users?
- Click the Save button, and the Compression Settings dialog will appear. What you see here varies depending on what file type you chose in the last step. In this case, use the settings in the text.
- Find the Assign Renderer section, and check to see that Production is selected instead of ActiveShade.
At this time, check that the viewport you want to be rendered is the currently selected viewport. The render engine will only render the currently selected viewport. If not, change it! (If you need multiple views in your movie, you make multiple renders and composite them together in another program like After Effects.)
- Click the large Render button in the bottom right corner of the Render Scene dialog box. Each frame in the timeline will be rendered separately and added to the output file.
Remember in step 4, when I told you to pick a folder to send the output to? Navigate to it (in Windows Explorer, not 3DS Max) and play the file.
Page 511 begins the discussion of Motion Blur, which is an effect that simulates not seeing a moving object clearly. Settings for Object Motion Blur are discussed:
- Duration - the number of frames that will be blurred
- Duration Subdivisions - the number of copies of the object that will be spread across the duration frames
- Samples - the number of duration subdivision copies that are actually used in the animation
The text cautions you to use as little motion blur as you can. It is a processor intensive process, and adding more can detract from the effect instead of improving it.
The text talks about the ActiveShade window, which is another view that can be requested in any viewport, with two exceptions: you can't use this view if the current viewport is maximized, and you can't use this view in more than one viewport at a time. The ActiveShade window is like a quick render view of the scene. It's a nice idea, in that you can keep making changes in other viewports, and the changes will update in the ActiveShade window as well. Well, sort of. Trying this out, I found some changes updated and some didn't, which kills some of the joy of it.
The text turns away from its main topic to consider cameras. The text explains that you will use two types of cameras in 3DS Max:
- target cameras are linked to an object in the scene to keep the camera looking at the object even when the object (or the camera) moves
- free cameras require manual settings; they do not automatically look at any object, nor do they move with the object. They are pointed at whatever they point at when they are created until they or the objects they point at are moved.
Basic camera shots are not discussed here, but they should be, along with some guidelines to categorize the shots you make. These guidelines are based on having a human being as the focus of the shot. For shots that do not include people, use whatever the main object is as the measuring stick:
- long shot - includes the entire subject, head to foot. Fred Astaire had a clause in his contract with MGM that said he was to be photographed this way every time he danced on screen.
- medium shot - shows a standing subject from the head to about the knees
- close-up - shows mostly the head of a subject, may include shoulders, but always ends above the waist
- extreme close-up - shows a portion of a face, or a portion of an object
- extreme long shot - people are often not visible in this shot that shows a cityscape, or landscape to establish the location of the next shot (also called an establishing shot for the obvious reason)
Camera shots can also be categorized by the angle of the camera (height above or below the subject), and by the kind of motion that the camera must make in the shot. Follow the link in the last sentence to read a discussion of these kinds of shots, which should help you to think more three dimensionally.
Camera lenses in the real world have characteristics that are related to their focal length. 3DS Max uses equivalent measurement to simulate the effects of longer and shorter lenses in its cameras. A related concept is Field of View (FOV). This is measure of how wide a portion of the scene a camera can see. The longer a lens is, the narrower the FOV. The shorter a lens is, the wider the FOV. In the real world, we need to change the lens on a camera to change the focal length. In 3DS Max, we can change to one of several Stock Lenses with a click on the Modify panel.
A rule of thumb for categorizing lenses:
- focal length 30mm or less - wide angle lens; makes the background look farther away from the foreground, includes more foreground than a regular lens
- focal length between 30mm and 200mm - standard lens, the extremes (30 and 200) will have some characteristics of the kind of lens they are closer to
- focal length 200mm or more - telephoto lens; makes the background look closer to the foreground
Chapter Exercise 2: Creating a camera
This exercise starts on page 515.
- Open the file specified in the text. Select the Top viewport.
- Click Create, Cameras, Target camera. Use the illustration at the top of page 516 as a guide to placing the camera in the scene. (Like creating a target light, drag from the camera to the target.)
- In this step you need to move the camera and the target. You can move them separately, but try the technique explained in the text: select the line connecting the camera to the target icon, and use the Move tool gizmo to move them to the desired height in the Front viewport.
- Pick a viewport to change to the camera's point of view. Note the explanation of what you should do and what can happen:
- Select a viewport and press the letter C.
- If a camera is currently selected, the viewport should change to the point of view of that camera.
- If no camera is currently selected, and if there are several cameras in the scene, you will get a dialog box to pick which camera to assign to that viewport.
- Quick Render the scene. Move the camera to better placement.
The text briefly mentions moving cameras. There are advantages to the cameras used in 3DS Max (and other virtual environments). We can move them as we like, without regard to the physical limitations a camera crew faces on a movie set. Some basic terms:
- panning - changing where a camera is pointed by rotating it
- trucking/tracking - changing where a camera is pointed by changing the camera's location; typically this term is used when a camera moves to follow a subject
- dolly in/out - moving the camera toward (into) or away from (out of) the scene
- push-pull - moving the camera toward a subject, then away from it
- crane effect - in movies, a crane shot places a camera on a crane that moves it above the scene. In 3DS Max, we will create a path for the camera to follow. The path must go where the crane would have put the camera.
- Follow this link to a Yale page about movie terms for more terms and a few example videos
We will move ahead to page 519, to consider the Render Elements tab of the Render Scene dialog. The idea here is that you can render parts of a scene separately, then modify each of those rendered images before you combine them in a compositing program. This makes the most sense for a single image or a series of still images. This approach lets you put great care into the production, but be aware that it slows you down to 1930s production speed. (Kind of like having to paint each individual frame.)
The text offers a list of parts of a scene that you might consider rendering separately:
- Alpha channel - this produces a matte that stands for the transparency of the objects in the scene
- Reflection - self explanatory
- Refraction - only the light that is changed by passing through material in the scene
- Self- illumination - self explanatory
- Shadow - self explanatory
- Specular - only the specular highlights in the scene
- Z-depth - a gray scale image of the scene in which objects farther from the camera are grayer than objects closer to the camera
On page 523, the text turns to Rendering Effects. These are special effects that are added as part of the render process, but after the scene itself is rendered. Think of it like adding a special effect to a motion picture. You shoot the scene with the actors first, then the special effect is added to what you shot. Unlike a motion picture, the effect is added in the process that "develops the film".
On page 526, the text discusses using raytracing to get "real" reflection and refraction in a scene. The text suggests that we can get realistic reflections in a scene with either a Raytrace material, or a Raytrace map. It recommends the map solution as taking less calculation (by the computer). It renders faster, but gives you less control and less detail than a Raytrace material. Unless we need the detail of the material, the text says to use the map.
The text proceeds to give us an example of each approach.
Chapter Exercise 3: Creating a Raytrace material
This exercise starts on page 527.
- Open the file specified in the text. Make sure one of the viewports is set for Camera01.
- Pick a sample slot in the Material Editor. Click the Get Material button. This time choose Raytrace material.
- Find the Raytrace Basic Parameters rollout. Change the color of the Reflect swatch from black to white, as instructed, to make the material as reflective as possible.
- Change the Diffuse color swatch to black.
- Apply the material to the column in the current scene.
The text breaks off the exercise to discuss the results. You should have a reflective material, but may notice jagged edges (jaggies) in the reflections. The text explains that the jaggies are caused by aliasing, an effect that rendering can cause unless antialiasing filters are turned on. In fact, the standard antialiasing filter is on, but the author wants to show you supersampling, which means filtering twice.
An interesting part of this discussion is the introduction of the Clone Rendered Frame Window button, a feature of the Quick Render window. The Clone Rendered Frame button opens a second window which is, at first, identical to the Quick Render you just made. However, you can make a change in the scene, and render to the new window, while keeping the old one open on screen. This is useful for trying out a change and seeing which version you should use. (You can undo the new change to return to the state of the previous render.)
The problem with this particular chapter is that the images supplied to show the effects of antialiasing and supersampling don't look any different from the images that show renders without these effects.
On page 528, the chapter turns to using a Raytrace map.
Chapter Exercise 4: Creating a Raytrace map
This exercise starts on page 528.
- In the same scene you used above, select a new slot in the Material Editor.
- Open the Maps rollout. Click the map button for Reflections. Select Raytrace, as you did in the last exercise.
- Click the Go to Parent button.
- Find the Blinn Basic parameters section, and change the Diffuse color swatch to black.
- Change Specular Level to 98 (bright), and change Glossiness to 90 (small).
- Apply this material to the column object and do a Quick Render.
- If you see aliasing, follow the procedure at the bottom of page 527 to apply supersampling and render again.
On page 530, the chapter turns to refraction. Refracted light is light that has been changed by passing through a medium like glass or water. In the exercise that is provided, it passes through a curved wine glass. The text warns you that rendering refraction takes significantly longer than reflection. (For more information on refraction, read the gray sidebar on page 533.)
Chapter Exercise 5: Creating a refraction with a Raytrace material
This exercise starts on page 530.
- Continue in the scene from the last exercise. Switch your Camera01 viewport to show Camera02.
- Pick a new sample slot in the Material Editor. Click Get Material.
- Choose the Raytrace material. (The one with a blue circle, not a green rhombus.
- Find the Raytrace Basic Parameters rollout. Change the color swatch for Transparency to white (transparent).
- Uncheck Reflect, and change the value to 20.
- The Index of Refr parameter is for the simulated Index of Refraction for the material. (Follow the link for a discussion of why different materials refract differently.) In short, the higher the value, the more the material bends light. Leave the IOR at 1.55.
- Find the Extended Parameters rollout (illustrated on page 531). Set the Reflections Type to Additive. Set Gain to 0.7.
- Find the Supersampling rollout. Follow the instructions the the text.
- Go back to the Raytrace Basic Parameters, and find the Specular Highlights group. Make the changes noted in the text.
- Apply the material to the wine glass in the scene. Do a Quick Render. You may want to arc rotate around the wine glass and render again to confirm the effect is working.
Read the discussion about changing the IOR value at the bottom of page 531. If you were going for realism, you could look up IOR values for various materials on the Internet.
The text repeats the procedure, but uses Raytrace mapping on page 532, to produce reflection and refraction. The render on this will take a LONG time compared to the others. For illustration, the image below followed this procedure for the wine glass, but used the Raytrace material method for the column/table top.
On page 534, the text turns to a project that puts together several skills from this chapter.
Project Exercise 1: Camera movement
This exercise starts on page 534.
- Open the project file specified in step 1.
- Click the Auto Key button to turn on key frame auto capture. Move the Time Slider to frame 45.
- Click the Camera viewport. Note the change in the Navigation Tools area, noted in the text. If you missed it, click another viewport, then switch to the Camera viewport again, and watch the change.
- Use the Dolly Camera tool as instructed to move the camera closer to the model.
- Use the Truck Camera (pan) tool to adjust the scene as instructed. It will look like you are adjusting the scene, not the camera.
- Use the Orbit Tool as instructed. You can think of it as adjusting the scene or adjusting the angle of the camera.
- The text tells you to use the Truck Camera tool again to get a view like the second illustration on page 536. You may find that you need to adjust with the Dolly Camera tool as well. Don't worry if you adjust several times, only the final position is saved in the key frame.
- Run the animation to check your work. Adjust as desired. Turn off Auto Key, and save incrementally.
The lesson continues by adding raytraced reflections to the scene. No more faking it, we want "real" reflections in our virtual studio.
Project Exercise 2: the rocket
This exercise starts on page 537.
- Continue with the scene from the last exercise. Open the Material Editor. Lots of materials are in use in this scene already.
- Select the first sample slot. It should already be named Rocket Body Left. The author explains that we do not need to change the material for the other side of the body, since we will not see it. This seems sloppy, but it actually speeds up the renders you will do.
- In this step the author uses a word (channel) in a way that I don't think he has used it before in this book. You should be aware that each of the named maps on the Maps rollout can be called a map channel.
Open the Maps rollout for this material. There should be no map assigned to the Reflection channel. (If one is assigned, drag a button that says None onto the map button for Reflection.)
- Change the value for Reflection to 20. Click the Reflection map button, choose Raytrace, and click OK.
- Do a Quick Render. You should see a difference between how the rocket looked at the end of the last exercise and now.
- Repeat the steps to add a Raytrace reflection to the materials for each of the parts listed in the text. These should be:
- FIN DECAL
- Wheel White
- Wheel Black
- Quick Render again to check your work, and save incrementally.
Project Exercise 3: the room
This exercise starts on page 538.
- Continuing with the last scene, in the Material Editor, select the material called FLOORS.
- Change the value for Reflection to 50 (50%), and set the map for Reflection to Mask.The will lead you to the two-button panel illustrated at the top of page 539.
- Click the button for Map. Choose Bitmap, and click OK. Navigate to the bitmap file specified in the text.
- You should see the Bitmap Parameters section. Find the Coordinates rollout, and change from Environ to Texture. This is the only change for this section.
- Click Go to Parent. You should see the panel with two buttons again. Click the Mask button and set it for Raytrace as you did for the materials in the last exercise.
- Quick Render to see the change in the scene. Improve the reflection by changing the Reflection value as instructed in the text.
In the rest of the chapter, the author fails to provide numbered steps. On page 540, he tells us how to turn Special Effects on and off for the current render. (They are turned on presently in your file.)
Starting at the bottom of page 540, he walks through creating a Quick Time movie of the 45 frames you have worked on. It is worth noting that 45 frames will be one and a half seconds at the default frame rate for Quick Time.