Basic Rendering Tutorial

There are 2 primary tasks when getting ready to render: selecting the render preset and setting the render size.

1. Launch the Render Editor from the Twilight Render toolbar.  The image area of the editor will be blank until you render an image.
2. Select the Render Preset.  Knowing what preset to choose is important.  Here are some important factors to consider.
   • Low/Low+ through High/High+ are considered 'biased' render presets.  They use a technique called Photon Mapping.
     • Biased presets have a definite completion.
     • Biased presets are actively anti-aliased (smoothing of jagged-looking edges).
     • Biased presets can take advantage of "fake" lighting such as non-emitting Emitter materials & lights with no shadow.
     • Biased presets are limited in the number of lights they can support.  Scenes with over 10 light-emitting faces should not use biased presets. Point and spot lights will render 10x faster than light emitting materials using biased presets.
   • Interior and Interior+ are considered 'unbiased' render presets.  They use a technique called Metropolis Light Transport.
     • Unbiased render presets have an indefinite completion.  You must stop them when you are satisfied with the result.
     • Unbiased render presets are rendered internally at 3x the selected size, then down-sized to create an anti-aliased image. This is known as "super sampling" and is important for image quality.
     • Unbiased presets render all light emitting materials, and all lights cast shadows.
     • Unbiased presets can handle a virtually unlimited number of lights and light emitting surfaces.
     • Increasing the number of light sources will increase render processing times in all methods. The greater the amount of direct light present in a scene will decrease render times in progressive methods.
   • Exterior preset is specifically designed for scenes with only sun and sky for lighting; no other lights should be present in the scene. Avoid HDR spherical sky lighting with Exterior preset. When using HDR with Exteriors it is suggested to use the Interior progressive unbiased render setting.
3. Select the size of the render.  Obviously, the larger the size, the more time the render will take and the more memory (RAM) it will consume.
   • If 'Fit to View Proportions' is checked, the final render size of your image will be a rectangle with the same Width-to-Height ratio as your SketchUp view.  The Width and Height will not be larger than your selected render size.
   • Clicking the Zoom button will set your Width and Height to exactly the current SketchUp view size.

In most cases, you will be rendering your scene without making adjustments to the Camera.  Naturally, Twilight Render uses SketchUp's camera view, including position, orientation, and focal length, to set up the render.  However, when necessary, you can make manual changes by editing the Camera settings in the Render Editor.

1. Click the Camera button to open the Camera settings drop-down
2. The 'Focal Length' is tied directly to your scene's focal length / field of view.  Changes you make to it in the Twilight Render editor will change the SketchUp camera, and vice-versa.
3. For very specific purposes, you can set the Film Height.  This will automatically adjust the Field of View to match the current SketchUp view.  You will probably only need to do this if you are trying to match a real-world camera setup.
4. The 'Projection' refers to how the 3D world is mapped to a 2D image.  This can be Perspective (Normal), Parallel, Cylindrical, or Spherical.  Perspective or Parallel are set by choosing 'SketchUp View' and then setting your SketchUp camera appropriately.
5. Depth of Field is what makes object in the foreground or the background more blurry than objects at the focal point.  By default, DoF is disabled so all your objects are rendered 'in focus'.  You can enable DoF by checking the Enable checkbox.
   • It's important to remember that DoF can considerably increase your render times.
   • When DoF is enabled, the camera acts like a real-world camera.  Smaller F-Number's result in a narrower 'in-focus' zone and stronger blurring outside of the focus target zone.
   • If DoF is enabled, make sure to set your SketchUp camera's Target.  This is the point that will be in focus.  You can set the target by launching the Twilight Render View Tool, holding down the Control key, and clicking on the focus point.

If your scene is organized by Layers, Twilight Render makes it easy to control what you render by enable or disabling Layers.  By default, whatever is visible in SketchUp is what get's rendered in Twilight Render.  If you hide a Layer in SketchUp, it isn't rendered.  However, you can make changes to disable or enable layers specifically for rendering.

1. In the Render Editor, click on the Layers button.  A list of layers will be displayed.
2. By default, layers will be rendered (a green check) or not rendered (a red X) based on the visibility of the Layer in SketchUp.
3. You can force a layer to be rendered by clicking on it once.  The icon will change from the SketchUp icon to a large green check.
4. You can force a layer to not be rendered by clicking on it again.  The icon will change from the green check to a large red X.
5. You can change back to the default SketchUp visibility by clicking on it once more.

There are some final options that you should know about to get the most out of Twilight Render. 

• Export your scene to Kerkythea XML by clicking the Export button.  Your scene and all resources, like images, IES lights, etc. will be saved to your specified location.
• Export your scene to a .Zip file, along with all the resources, by click the Export to Zip button.
• Twilight Render performs multi-threaded rendering.  You can control the number of threads by choosing Multi-Threading from the Settings menu.
• Choosing 'Advanced Render Settings' from the Settings menu will allow you to disable Volume Transfer.  This may help speed up your render time, but should not be checked for any scene with translucent or volumetric materials.
• The 'Save Method' allows you to choose to Manually save your images (the default), Presave your image which requires you to select a filename before rendering, or save at a specific time interval.  If you are performing a long-time render, choosing one of the interval methods will ensure your image is saved regularly in the event of a SketchUp crash or computer power down.
• Flatten all Geometry means that Twilight Render will treat all components and groups as if they have been exploded.  Ordinarily this is not an option you will choose but may be useful for scenes encountering odd problems.
• Flatten all Nested Components means that Twilight Render will treat all nested components as if they have been exploded.  This is used primarily to force Section Cuts inside components to cut into nested components (which it doesn't do normally).  However, this may dramatically increase the model processing time.
• The Render History dialog can be opened from the Settings menu and will present you with a list of all the images that have been rendered or saved during your current session.  You can open a previously rendered image and save it, but you can not edit it within Twilight Render.