Understanding the linear workflow
Video: Understanding the linear workflowAs things go in the 3D world, linear workflow is a fairly controversial subject. It was introduced in CINEMA 4D two versions ago, and it dramatically changed how 3D images are rendered in the render engine. Rather than go through a lengthy discussion about the technical aspects of linear workflow, I want to focus on it from an artist perspective. Linear workflow relates to the way that images are displayed on a computer screen and that method involves something called a Color Profile. It can be really daunting for an artist who's not technically-minded to even deal with the idea of linear workflow.
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CINEMA 4D Essentials with Rob Garrott is a graduated introduction to this complex 3D modeling, rendering, and animation program, which breaks down into installments that can be completed within 2 hours. This installment covers the basics of rendering images and animation and compositing those elements and effects together into a single movie. Rob shows how to optimize your render settings and configure batch rendering for maximum efficiency. On the compositing side, he shows how to use the compositing tag and object buffers to create a flawless composite, and how to round-trip assets between CINEMA 4D and After Effects.
- How the CINEMA 4D render engine works
- Adjusting the render settings
- Rendering still images and animation
- Setting up multipass rendering
- Understanding the linear workflow
- Rendering and importing elements from After Effects
Understanding the linear workflow
As things go in the 3D world, linear workflow is a fairly controversial subject. It was introduced in CINEMA 4D two versions ago, and it dramatically changed how 3D images are rendered in the render engine. Rather than go through a lengthy discussion about the technical aspects of linear workflow, I want to focus on it from an artist perspective. Linear workflow relates to the way that images are displayed on a computer screen and that method involves something called a Color Profile. It can be really daunting for an artist who's not technically-minded to even deal with the idea of linear workflow.
But the most important thing to remember about it is that it changes how the lights and materials behave and it also changes how the blending modes behave when you get into After Effects. So I've got a scene here and linear workflow is on, and linear workflow has been on for all the renderings that I've been showing you so far in this course. And where you adjust the linear workflow is in the project settings. Now if your project settings aren't visible, you hit Command+D or Ctrl+D on the keyboard to bring up the Project settings. And let's raise this window up just a bit.
Right here at the very bottom is this little unassuming button, Linear Workflow. Unfortunately, that button defaults to on. That is not a big deal for a lot of situations. If you're going to be rendering just a still image with no multipasses, then linear workflow is not a big deal, because what you see is what you will get when you go in After Effects. However, when you start to get into multipass rendering, linear workflow becomes crucial, and that button will have a dramatic impact on how the images behave when you get into After Effects. So before we get in to After Effects, let's take a look at linear workflow, both off and on.
So I've got linear workflow on for this rendering and I'll hit Command+R or Ctrl+R on the keyboard. You can see my rendering looks pretty good. There is a nice murky sort of overtone to the image. It's under water, and we've got our fish swimming past the linear workflow type. Now let's turn it off and you can see a very different image. First thing you'll notice is that the work space changed here. The materials changed on the material manager and when I render, it's going to look very different as well, Command+R or Ctrl+R again.
You should notice that the image is darker. The number one thing that linear workflow does is it changes how the lights and materials add together. It's going to be easier to see this with the side-by-side comparison. So I've got two different renderings, one with and one without linear workflow that we're going to open in the Picture Viewer. So let's go to the Window menu and you can then go to the Picture Viewer. And let's go to the File > Open, and let's navigate to our rendering folder in the exercise files. And let's grab linear-workflow- OFF and then Open that one.
And let's do that File > Open again, and then grab linear-workflow-ON, and then Open that one. Now over here in the history, we can see we've got linear workflow off and on, and we can click back and forth between these two, and you can see the dramatic difference between the renderings. Now there is technically no right or wrong answer here. To me, personally, the wrong answer is that linear workflow is on by default. What happened when it was introduced a couple of versions back is that it changed how the renderings behaved by default. If you opened up old projects that had linear workflow off then they would come in with linear workflow off.
But anytime you created a new project, linear workflow would defaults to on, and so, when you got into After Effects with a multipass render, your renderings will behave differently. And a lot of folks didn't understand how to deal with that, so that's what I want to focus on today, is how to deal with that linear workflow. Let's close up the Picture Viewer. Now I've got the render settings all set for linear workflow. Let's bring up the Render Settings here by hitting Command+B or Ctrl+B on the keyboard. And before I go any further, I want to turn Linear Workflow back on, so that I leave it on for this demonstration.
I've got my Render Settings set, I've got Object Buffer set, I've got my RGB image. I've got all my elements rendered here correctly. Rather than render this image out and go through the time-consuming process, I've pre-rendered it already. And you can see under the Output dialog that I've rendered frames 45 to 89. I wanted to minimize the file size for download of the project assets. When it comes down to working with linear workflow, there's two very important options under the Save options of the Render Settings. Let's click on the Save option and the first one is the Bit Depth. Now the Bit Depth should always be 16 bit.
And because it has to be 16 bit, it limits the options for your format. You have to use a format that supports 16 bit depth. QuickTime does not support 16 bit depths so you have to render to an image sequence. The preferred image sequence for me is a Photoshop. The next most important setting is the Image Color Profile. It defaults to sRGB. And to be honest, I normally just leave it on that. For other color profiles, you can load one in, if you've been sending a specific color profile for a project. You can also low run from your monitor that you're currently working with.
The problem with that though is that most folks don't have their monitor set correctly, so you want to be really careful. I generally leave mine on sRGB, because it's a good generic starting point and it creates an even base for my work. So those are the two most important settings when you're working with linear workflow. Linear Workflow should be on. You just need to render to 16 bit and you leave this image color profile set the way it is. So with these render settings, I rendered the image out. Let's move over to After Effects now and import that rendering in. So here we are in After Effects and I'm going to go to File menu and do an Import > File.
So I'm going to navigate to the exercise files, to the rendering, to the C4D Rendering, to the linear workflow, and let's scroll all the way down and grab the linear-workflow.aec. Now if this aec file is grayed out for you, that means you do not have the correct After Effects import plug-in installed in After Effects. I'm going to cover this in much more detail in the next chapter. So for now, if your aec file is grayed out, then just follow along. Let's hit Open. It's going to think about it for just a moment. And now I get two folders in the project window, Linear Workflow and Special Passes; it's called linear workflow, because that's what I named my rendering inside of CINEMA 4D.
I'm going to take the Special Passes folder and drag it into the Linear Workflow folder. That's the first step I always do when I import. And I will twirl that open. You could see I have a linear-workflow comp here. Let's double-click on that and I'm seeing black here at the top, because of the render settings that I had in CINEMA 4D. In CINEMA 4D, I had adjusted my render settings in the Render Settings window to render just frame 45 on, and I did not adjust my preview range, so it gives me this gap here. I'm going to scrub through this gap to the very first frame, which is at frame 45 or 115 on the timeline, and you can see that I've got a very dark image.
This is what you'll see if your linear workflow is not set correctly in After Effects. In order to see what it's supposed to look like, let's import the linear workflow on JPEG from our Project Files folder. Hit Command+I or Ctrl+I on the keyboard and then in the Project Files folder is the linear-workflow-ON. So once again, this is inside the exercise files and rendering, and then loose in there is linear-workflow-ON. Do not accidentally import linear-workflow-OFF. We want that on one. So let's hit Open.
And if I double-click on that, I'm going to see what my rendering is supposed to look like. When you're not dealing with multipasses, linear workflow does not matter. You will see the correct image from CINEMA 4D and this is a great example of that. This JPEG comes in just how it's supposed to look in CINEMA 4D. So that begs the question, how do we get it to look right in After Effects? The way we do that is a multistep process. So here's our composition. We have to go to the File and go to Project Settings at the very bottom.
And in the Project Settings, let's raise that up, the very bottom of the Project Settings window is getting cutoff because of the resolution of the screen record that we're doing. But you can see I've got OK down there at the bottom. So the linear workflow starts by changing the bit depth. The linear workflow cannot work in anything less than 16 bit, so we're going to go to 16 bit and that matches our rendering from CINEMA 4D. So we turn on 16 bit. Now we can change the working space to match the render setting that we had in CINEMA 4D. If you remember, I pointed out two very important settings in CINEMA 4D render settings for linear workflow, and that involved the color profile, and this is the color profile that matches the one we used in CINEMA 4D.
So when we select that, now we get this button active that says Linearize Working Space. We're going to turn that on and then when we hit OK, now we see the image that looks the same as it did from CINEMA 4D. And you see if I click through, this is a different frame of the animation, but if I go back here, you can see that my rendering now looks the way it's supposed to in After Effects. Whether you like it or not, linear workflow is here to stay, and if you're going to be working in CINEMA 4D and After Effects, you need to get used to either turning it off or dealing with it.
For some projects I'd like to have it off. For some projects that I know are going to have a lot of gradients, or if I'm going to have to have a do lot of manipulation of the multipasses, I will leave Linear Workflow on. I'll let the client know ahead of time though that I'm dealing with linear workflow, so that they know ahead of time, if I have to deliver the project files to them, they need to adjust their workflow internally as well. So regardless of what you decide to do, the important thing is to be specific and be proactive about it, and deal with those settings upfront.
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