Particles

This visual element is responsible for rendering the particles. Typically, particles are visualized as simple spheres, but you can switch to other, more complex geometric shapes if desired. The Particles visual element provides parameters controlling the standard visual representation of particles.

Settings hierarchy

OVITO uses a three-level hierarchy to determine the final appearance of each individual particle:

Per-particle properties (highest priority): Properties like Color, Radius, and Transparency defined for individual particles always take precedence if present. See Per-particle properties below for details.
Per-type settings (medium priority): Settings configured for each particle type through the Edit types modifier. These include type-specific radius, color, and shape. Per-type settings can also include custom mesh shapes for advanced visualizations.
Default settings (lowest priority): The default particle shape and radius values configured in this visual element serve as the final fallback.

This hierarchy allows flexible control: you can set defaults that work for most particles, customize specific types (e.g., different radii for different atomic species), and still override individual particles when needed (e.g., highlighting specific atoms using selection and coloring modifiers).

To modify these settings:

Per-particle properties: Use the Compute property modifier or more specific coloring modifiers
Per-type settings: Use the Edit types modifier
Default settings: Configure them directly in this visual element panel

Per-particle properties

On the primary level, the visualization is affected by certain properties of the particles themselves, listed in the following table. By setting these particle properties, for example using the Compute property modifier, you can fully control the visualization on a per-particle basis.

Particle property	Data type	Description
`Color`	Real (R,G,B)	Display color of individual particles. Red, green and blue components must be in the range [0,1].
`Radius`	Real	Display size on a per-particle basis.
`Transparency`	Real	Transparency of individual particles. Must be in the range [0,1].
`Aspherical Shape`	Real (X,Y,Z)	Dimensions of particles with a non-spherical shape. The exact interpretation depends on the particle shape.
`Orientation`	Real (X,Y,Z,W)	3D rotation of particles with non-symmetric shapes, specified as a quaternion. See Controlling size and orientation of particles for further information.
`Superquadric Roundness`	Real (X,Y)	Roundness parameters for superquadric particles.
`Selection`	Integer	Marks currently selected particles (1 = selected, 0 = unselected). Selected particles are highlighted in red (only in interactive viewports but not in rendered images).

To see the list of particle properties present in your dataset, open the data inspector panel.

Parameters

Universal settings

These settings apply globally to all particles in the system:

Radius scaling

This global scaling factor (percentage) is applied to all particle radii at rendering time. It is applied in addition to any other factors controlling the size of particles (per-type radius, per-particle radius, default radius). By setting it to a value below 100%, you can generate a balls-and-sticks visualization of molecular systems, with reduced atomic spheres connected by cylindrical bonds.

Rendering quality

This parameter controls the method used for rendering spherical particles in the interactive viewports using the OpenGL renderer. The following modes are available:

Automatic (default)

OVITO automatically selects the rendering quality based on particle count:

Less than 4,000 particles: High quality
Between 4,000 and 400,000 particles: Medium quality
More than 400,000 particles: Low quality
High quality is always used for final output images regardless of particle count

Low

Particles are rendered as texture-mapped imposters facing the viewer. Particles do not have depth in this mode, and intersections between overlapping particles may not be displayed correctly. This mode offers the best performance.

Medium

Particles are rendered as texture-mapped imposters facing the viewer. An OpenGL fragment shader computes depth information for each pixel to produce reasonable sphere-sphere intersections for overlapping particles.

High

Particles are rendered as true spheres using an OpenGL fragment shader that computes the ray-sphere intersection for every rendered pixel. This provides the best visual quality.

Default particle shape

These settings provide default values for particles that don’t have shape or size specified via per-type settings or per-particle properties:

Style

Selects the default display shape for particles. The shape can be overridden on a per-type basis (see the note above about the property hierarchy). Available shapes:

Sphere/Ellipsoid

Particles are rendered as 3D spheres by default. This mode supports several advanced variations:

With Aspherical Shape property: Particles become ellipsoids where the three components (X,Y,Z) control the half-lengths of the principal axes (the Radius property is ignored).
With Superquadric Roundness property: Particles are rendered as superquadrics with controllable roundness.
The particle’s Orientation property, if present, rotates the ellipsoid or superquadric.

Circle

Particles are rendered as flat discs that always face the viewer. Note that some rendering engines may not support this mode.

Cube/Box

Particles are rendered as cubes by default, with the Radius property controlling the edge half-length.

With Aspherical Shape property: Particles become rectangular boxes where the three components (X,Y,Z) specify the half-lengths along each axis.
The particle’s Orientation property, if present, rotates the box.

Square

Particles are rendered as flat squares that always face the viewer. Note that some rendering engines may not support this mode.

Cylinder

Particles are rendered as cylinders aligned along the Z-axis by default.

The Aspherical Shape property is required: Its X-component controls the cylinder radius, its Z-component controls the cylinder length.
The Orientation property rotates the cylinder from its default Z-axis alignment.

Spherocylinder

Particles are rendered as cylinders with hemispherical caps (capsules). Configuration is identical to the Cylinder mode above.

Radius

Specifies the default particle size (in simulation distance units) used as a fallback when the size is not specified via per-particle or per-type settings. This value is only used for particles where:

The Radius particle property is absent or zero, AND

The particle’s type (from Particle Type property) has no radius defined or has radius = 0