Render settings

The Rendering tab of the command panel contains all settings related to image and movie rendering. To start an image/movie rendering process, use the Render active viewport button located at the top of the page or the button in the toolbar located above the viewports. OVITO will always render the currently active viewport, which is indicated by a yellow border. Right-click in a viewport to make it the active one.

Below the render button, a tab bar organizes the settings in four groups:

Output: Rendering range, output image size, output file, and background.
Renderer: Selection of the rendering engines for output images and for the interactive viewports, and the settings of these engines.
Effects: Visual effects supported by all rendering engines (outlines, fog, depth of field) and the direction of the light source.
Materials: The rendering materials of the scene, which define the surface appearance of the objects.

The ? button next to the tab bar opens the help topic for the currently selected tab.

All of these settings are part of the current session and are saved in session state files, with one exception: the rendering engine used by the interactive viewports is a setting of the OVITO installation on your computer.

By default, rendered images are displayed in the so-called frame buffer window after rendering is complete, but they are not automatically saved to disk. That means they will be lost as soon as you close the frame buffer window or quit OVITO. To save rendered images, you can either use the Save to file function found in the toolbar of the frame buffer window after rendering is complete or activate the Save to file option in advance on the Output tab, which is described below.

When rendering a movie note that the total length of the animation and the playback speed (frames per second) are set in the animation settings dialog, which can be opened using the Animation settings button.

Output tab

Rendering range: Selects which animation frame(s) to render. If you decide to render an animation, i.e. a range of frames, make sure you also turn on the Save to file option and set an output filename below. Otherwise, the rendered animation will not get permanently saved to disk.
Every Nth frame: This value determines which fraction of animation frames is actually rendered. Setting this parameter to 1 renders every animation frame. A value of 2 will render only every other frame, etc. Thus, you can use this to reduce the number of generated video frames in case of extremely long simulation sequences.
File number base: When saving the frames of the animation as a series of image files (rather than a single movie file), OVITO automatically appends the frame number to the output filename. This setting lets you specify another base file number, i.e. an offset. This can be useful if you want to collect the video frames from several animation sequences in one directory and later combine them into one contiguous movie using an external video encoding software.
Output image size: Sets the width and height of the rendered image or movie in pixels. Note that you can activate the preview mode for an interactive viewport window to see exactly which rectangular area of the viewport will be visible in the final output image.
Preview visible region: This option activates preview mode for the current viewport window, which means it will display a rectangular frame indicating the area that will be visible in the rendered output image. The aspect ratio of the rectangular guide is determined by the output image width and height.
Render all viewports pro: Activate this option to generate a composed output image with multiple side-by-side views of your 3d scene. The arrangement of the views is determined by the current layout of the interactive viewport windows. Note that you can modify the number, size and layout of the viewports by dragging the vertical and horizontal lines separating the viewport windows.
Save to file: This option tells OVITO to save the rendered image or movie to disk in addition to displaying it in the frame buffer window. Use the Choose… button to pick an output filename. When rendering an animation sequence, all animation frames will be written to a single movie file if you pick a video format such as AVI or MPEG (see Video encoding). If you choose an image format (e.g. PNG, JPEG), OVITO will instead produce a sequence of image files, one per frame. In this case, the frame number will automatically be appended to the base filename you provide. Alternatively, if the filename contains a “*” wildcard character, it will be replaced by the frame number.
Background: You can choose between a uniform background color and a transparent background. In the latter case, OVITO will make those areas of the output image transparent that are not covered by any objects. This is useful if you intend to put the image in front of some other background later, for instance on a presentation slide. Note that transparency information (alpha channel) must be supported by the output format for this to work. Best choice is the PNG file format.

Renderer tab

OVITO Pro offers several rendering engines, which differ in terms of visual quality and rendering speed. See the Rendering page for a list. The top part of the Renderer tab selects which engines are used:

Images/videos: The rendering engine that generates output images and movies when you click Render active viewport. This choice is part of the session state.
Viewports: The rendering engine used by all interactive viewports for the real-time display of the scene. Besides the Standard renderer, which is the default, OVITO Pro offers the VisRTX renderer on computers with a suitable NVIDIA GPU. This choice is a setting of OVITO on your computer and is not saved in session state files. You can also change it in the Viewport Renderer submenu of the viewport menu or on the viewport settings page of the application settings dialog.

The panel below shows the settings of the selected rendering engine. Each engine has only one set of settings per session: if you select the same engine for images/videos and for the viewports, the interactive viewports show the scene with exactly the settings used for rendering output images. If you select two different engines, the Edit settings for control lets you choose which of the two engines’ settings are displayed. The settings of an engine are preserved when you switch to another engine and back.

Effects tab

These effects enhance the depth perception in rendered images and in the interactive viewports. Because they are not specific to any one rendering engine, they are configured here and are preserved when you switch to a different engine. Effects that only a particular rendering engine provides, such as ambient occlusion and shadows, are found among the settings of that engine on the Renderer tab.

Outlines

Enables the drawing of outlines along object edges. The outlines are depth-aware, meaning that they are only drawn when the depth difference between two overlapping objects exceeds a certain threshold. Optionally, the width of the outlines can be adjusted based on the depth difference, which can help to improve visibility of outlines in complex scenes.

Width mode: Uniform draws all outlines with the same line width. Variable makes outlines wider the larger the depth difference between the surfaces on either side of an edge, which emphasizes the silhouettes of objects that stand out far in front of the objects behind them.
Depth threshold: Outlines are only drawn along edges where the depth difference between the adjacent surfaces exceeds this value, which is specified in the length units of the simulation. Increase it to suppress outlines between objects that touch or overlap, e.g., between bonded atoms.
Line width: The width of the outlines in pixels. In Variable mode, you specify two widths: the width of outlines at the depth threshold and the maximum width reached at the end of the ramp.
Ramp length: Only used in Variable mode. The outline width increases linearly from the first to the second line width as the depth difference grows from the depth threshold to the depth threshold plus the ramp length. Outlines along edges with even larger depth differences keep the maximum width. A ramp length of zero draws all outlines with the maximum width.
Custom Color: When disabled, the outline color is automatically determined based on the background color: white outlines for dark backgrounds and black outlines for light backgrounds. When enabled, the manually selected color is used instead.

Fog

../../_images/depth_cueing_on.png — With depth cueing enabled, distant objects gradually blend into the fog color.

../../_images/depth_cueing_off.png — With depth cueing disabled, it becomes harder to identify individual objects in dense scenes.

Enables depth cueing: objects are gradually blended into the fog color with increasing distance from the viewer, which makes it easier to perceive the depth arrangement of objects in dense three-dimensional structures. By default, the fog takes on the background color, so that distant objects fade into the background. The effect applies to all objects of the three-dimensional scene, including semi-transparent ones; viewport layers and other two-dimensional overlays are not affected.

Scene depth: The depth range over which the fog builds up. Both values are specified relative to the depth extent of the scene as seen from the camera, i.e., 0% corresponds to the point of the scene’s bounding box nearest to the camera and 100% to the farthest point. Objects in front of the From depth are not affected by the fog. The fog opacity increases linearly up to the To depth, where it reaches the specified intensity. Because the range is defined relative to the scene extent, the effect does not depend on the scale of the model or the camera distance.
Intensity: The maximum opacity of the fog, which is reached at the To depth and beyond. At 100%, the most distant objects vanish completely in the fog.
Custom Color: When disabled, the fog color is the background color of the rendered image (or the viewport background color in the interactive viewports when preview mode is off). When enabled, the manually selected color is used instead.

Depth of field

When depth-of-field rendering is active, only objects located in the focal plane appear sharp. Objects closer to or farther from the camera appear blurred. The focal plane is perpendicular to the viewing direction and passes through the focal point or lies at the fixed focal length from the camera. The ray-tracing rendering engines (Tachyon, OSPRay, and VisRTX) simulate a physical camera lens. The Standard renderer approximates the effect by blurring the rendered image according to the depth of each pixel, which also makes the effect visible in the interactive viewports. The effect requires a perspective projection and has no effect in viewports using a parallel projection.

Focus on

Selects whether the camera focuses on a point in the scene (the default) or at a fixed distance from the camera. The input fields below show the parameter of the selected mode:

In point mode, the xyz coordinates of the focal point. The focus stays on this point when you move the camera or when the camera is animated. If the focal point lies behind the camera of a viewport, the effect is turned off for that viewport. When you turn on the effect for the first time, the focal point is placed at the center of the scene.
In distance mode, the focal length, i.e., the fixed distance from the camera at which objects appear sharp, specified in simulation units of length. The focus then stays at this distance when the camera moves.

Pick in viewport

To focus on a specific object, click this button and then on the desired object in a viewport. In point mode, this sets the focal point to the picked location. In distance mode, it sets the focal length to the distance of the picked location from the camera.

Aperture

The radius of the camera’s lens aperture, specified in simulation units of length. Larger values blur objects away from the focal plane more strongly (default: 0.5).

Light direction

The direction of the directional key light source, which illuminates the scene from a fixed direction relative to the camera. When you rotate the viewport camera, the light source moves with it. All rendering engines place their direct light source accordingly, and the Standard renderer casts its shadows from it. The Standard renderer moves the specular highlights and the diffuse shading of objects along with the light source; with the default direction, objects look as in earlier program versions of OVITO.

Latitude, Longitude: Direction of the light source relative to the viewing direction, specified as two angles. At 0° latitude and 0° longitude, the light source is located directly behind the camera and casts no visible shadows. Positive latitudes (up to 90°) move the light source upward, positive longitudes (up to 180°) to the right. The default direction is 10° latitude and -10° longitude.