Aaron F. Ross |
Tuesday, April 1, 2014
Maya’s Camera Sequencer is an amazing tool for nonlinear editing and previsualization. It lets you create a cuts-only edit of multiple cameras and shots within a single scene, and render the edited sequence out to a Playblast. There’s just one catch: By default, the framing and aspect ratio of the exported sequence doesn’t match that of the cameras. I wasn’t able to cover this in my recent course Cinematography in Maya but in this article, I’ll describe how to work around the issue.
With the following steps, the Maya Camera Sequencer can render movies and image sequences with the same crop factor as the Batch Renderer. Depending on your needs, you may even be able to render final production animations using Viewport 2.0! Imagine that: You can stage, animate, and edit an entire movie within Maya, basically erasing the distinctions between pre-production, production, and post.
The problem arises because unlike a standard Playblast, the Camera Sequencer can’t display the Resolution Gate. The Resolution Gate shows the renderer’s crop factor in the viewport. With it enabled, what you see in the viewport matches the rendering. Without the Resolution Gate displayed in a Camera Sequencer Playblast, we get the full viewport frame crop, not the renderer frame crop.
Before you begin, make sure you’ve framed all of your shots as desired using the Resolution Gate. You can enable that from Maya’s Viewport Toolbar, or from each camera’s shape node attributes, under Display Options > Display Resolution.
The key to an aspect-correct Playblast process is ensuring that the viewport displays exactly the cropping you desire, without use of the Resolution Gate. For each camera in your sequence, you’ll need to make some changes.
Go to the camera’s shape node attributes. To see the effect of what you’re doing, scroll down to Display Options.
• Enable Display Film Gate.
In the Film Back section, set the Camera Aperture size to match the aspect ratio you wish to render. It’s important to know that if you change the Aperture Width, then the cropping will change. So, to maintain the current crop factor, only change the Aperture Height. To find the correct value for Aperture Height, simply divide the current Aperture Width by the desired aspect ratio.
For example, if rendering to HD 16:9, for an aspect of 1.778:
• Leave the Aperture Width at its default of 1.417 inches.
• Set the Aperture Height to 0.797 inches (1.417/1.778 = 0.797).
At this point, the Film Gate and Resolution Gate are identical. Go back to the Display Options. Force the viewport renderer to display the full aperture.
• Disable Display Film Gate.
• Disable Display Resolution.
• Set Overscan to 1.0.
With Resolution Gate off, and Overscan set to one, now we’re flying blind. We can’t see the correct crop factor in the viewport, so it’s important that our framing was already locked before we get to this stage. The Playblast engine will render the framing that we previously set up with Resolution Gate enabled.
Go to the viewport that displays the output of the Camera Sequencer. If necessary, choose View > View Sequence Time from the Panel Menu. Choose the viewport rendering mode, such as Renderer > Viewport 2.0. Make the viewport display look the way you want it to. Just be sure your video hardware can handle all of the features you enable.
What you see in the view is what you will get when you create the Playblast. Choose the desired shading mode, for example, Lighting > Use All Lights, enable Shadows, and so on. For full control, set the specific viewport renderer options, such as Renderer > Viewport 2.0 > Options. Here you can specify texture resolution, antialiasing quality, ambient occlusion, and more.
Next, we need to hide everything in the viewport except scene geometry:
• Choose Show > None from the Panel Menu. This hides everything in the viewport.
• Also disable the viewport interface elements by unchecking Show > Manipulators, Show > Grid, and Show > HUD.
• Then enable Show > Polygons, Show > NURBS Surfaces, or anything else you wish to render.
Be warned: The Show > Playblast Display menu doesn’t work in conjunction with the Camera Sequencer.
In the Camera Sequencer, choose Playblast > Playblast Sequence > Options. By default, Playblasted movies will be saved into the current project’s /movies directory. You’ll need to choose a File Name; I advise using the current scene file name as the movie file name.
Set the Resolution Width and Resolution Height to your desired pixel values. Make sure those pixel values work out to the same aspect ratio that you determined in the Camera Aperture settings.
In this example, we’re rendering to HD 16:9:
• Resolution Width = 1280
• Resolution Height = 720
• Device Aspect Ratio = 1.778
• Pixel Aspect Ratio = 1.0
If the desired output resolution is larger than the available screen area for a single viewport, we’ll need to enable the Offscreen option.
• Offscreen = enabled
In this case, Maya will render the Playblast at the desired resolution, without being constrained to the size of the viewport. We won’t be able to see the rendering as it happens, but we can track render progress by observing the current time indicator in the Camera Sequencer.
For test renders, I advise the following settings:
• Format = qt (QuickTime)
• Encoding = h.264
• Quality = 100
If using the Camera Sequencer for final output, you’ll want to render to an image sequence:
• Format = image
• Encoding = PNG (thumbnails supported in Windows and OS X)
If rendering to an image sequence, the files will be stored in the current project’s /images folder. By default, Maya will create a subfolder called /movies, and your frames will end up in /images/movies. To better control where files get stored, click the Browse button and explicitly navigate to the current project’s /images folder. Then, in the File Name field, enter a subfolder name followed by a forward slash, then a file name. For example, playblast01/sequence01 creates a folder called /images/playblast01, and inside that folder is a sequence of images with the naming convention of sequence01.0001.png.
That’s it! The Camera Sequencer is now not just a previz editor, but a full-blown production renderer!
Tags: 3D Rendering, Camera, Maya, Rendering, Sequencer, Tips
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