Mastering 3D Rendering in Blender

Following along with our series on Blender, we have been promising to go in depth into the rendering aspect of the software. Once you’ve created your scenes in Blender 3D, how do you render them out as high quality stills and video?

In this article we cover the rendering engines, the settings for rendering, quality levels, file types and all issues connected with taking your Blender scenes and making them into still images and video sequences.

The basics of rendering are as follows. You need to set the size of the frame your camera will capture, and you need to set the quality of the rendered image. If you are capturing stills, you need to know how to save. If you are rendering animation, you need to set the file type of the video file and save them as a sequence.

The settings for rendering are located on the right-hand side of the properties panel.

Note: properties panel buttons are “contextual;” that is to say depending on what you have selected in the 3D view, you will see a different row of buttons in the panel. Click an object or a camera, and you will get different buttons for each.

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If you click the little camera button on the Properties toolbar, the top panel marked “Dimensions” sets the image size of your renders. This is not anything to do with the camera or lens. This is the size or dimensions of the final video or still.

There are presets in a drop-down, and usually for video you will set a preset HD video size from here like 1920×1080 or 1280×720. But for still images, these figures can be anything you like.

Frame range means that you can set a start frame and an end frame of your video. For example, if you want a five-second video, and the frame rate is set as 25 frames per second, you will set the start frame to “1” and end frame to “125” to get 125 frames of animation.

And about frame rates: If you come from an NTSC country, you will be used to using 30 frames per second or fps. In PAL countries you will be used to using 25 frames a second. Blender defaults to 24 frames per second.

If your entire video is going to be standalone animation, then you can leave it like that. But if you need your footage to integrate with footage from cameras, you need to know which fps they use. If your camera captures in 30fps, then you need to set Blender to 30fps to make animation that will cut together with the live footage. The same goes for cameras which capture at 25fps.

In Blender there are three rendering engines, and I’m going to tell you about two of them. Don’t worry too much about what it means for now, but suffice it to say they are different methods of calculating the image. Don’t worry about the Blender Game engine. For now we are going to concentrate on the other two.

Blender Render is the default render engine, and it’s good for basic rendering. It’s fast and it’s simple, but it uses very basic lights, textures and rendering quality. The light rays don’t bounce around like they do in real life, and the images you get with it, for the most part, are simple computer graphics-looking images.

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This is perfect for logos and motion graphics, etc. If you want fast, or “quick and dirty” as they say in the trade, then Blender Render is your man.

Cycles Render is the highest quality render engine in Blender, and it calculates many light beams. They bounce around like light does in real life. If you want the ultimate quality that Blender can deliver, then always use Cycles Render.

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The quality you get with Cycles is clearly superior with subtle light reflections and realistic light physics. Always use it in preference to Blender Render when you have the computing power and need the quality.

There are two ways to set the quality of your render. One that goes for either render engine is the Output panel. Here you can set the quality for a still, like a JPG, where you can set the percentage quality. It is here you can also set the location of your saved files and videos by clicking on the little folder icon beside the word “/tmp/.” If no location is set, then the files are rendered to screen.

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The second quality setting only becomes available if you are using the Cycles Render Engine and that is Sampling. This is a tricky concept, and it basically means the amount of light rays that the scene will produce and render.

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The more light rays, the more times they bounce around, the more realistic the scene. But the more light rays, the more time it will take to render. So it’s a tradeoff.

Fortunately, there are presets set for you on a drop-down to set sampling for Preview renders and Final renders. Use Preview to see what it looks like, then set Final for the final render.

And finally, in the output settings you set what kind of media, still or video, you want to render and the file type. Usually still graphics are PNG or JPG, and you get to set the quality as a percentage.

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For video file types, you can choose from many formats, but the only ones you should concern yourself with are either XVID and AVI for PC users or H264 and MOV for Mac users. Select RGB rather than RGBA unless you want to save Alpha channels. (If you need to ask us what those are, then you don’t need to save them. We’ll be covering alpha channels and their uses in a future article.)

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When you are all set and ready to render, you can “push the button.” To render a frame, either hit the F12 key on the keyboard or click the “Render” button in the Render panel. To save the image, press F3 and type a filename, and set the location of the saved file using the browser.

To render an animation, click the Animation button or press “Ctrl + F12” on the keyboard; the target location to save the animation to can be set in the output panel.

Now you know how to render your scenes in Blender. We will be doing more on rendering when we tackle some advanced camera topics like Depth of Focus (DOF) in a future article. Keep your eye out for that.

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If you have any questions about rendering in Blender, please don’t hesitate to mention it in the comments below.

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