# Particle display

This display object is responsible for rendering particles, and its parameters control the visual appearance of particles. You can open this parameter panel by selecting the Particles entry in the pipeline editor.

## Parameters

Shape

  Selects the visual shape of particles. Note that spherical particles can be turned into ellipsoidal particles by setting the `Aspherical Shape` particle property. Similarly, the size of box-shaped particles can be controlled with the same property.

  The size of cylindrical and spherocylindrical particles is also controlled by the `Aspherical Shape` property. Here, the component `Aspherical Shape.X` determines the radius of the cylinder, and `Aspherical Shape.Z` determines its length. The vector component `Aspherical Shape.Y` is ignored.

  The orientation of ellipsoidal, box, and cylindrical particles can be controlled using the `Orientation` particle property. With this property, a quaternion can be specified for each particle which determines its orientation in space. If the `Orientation` property is not defined, all particles will be aligned with the global simulation coordinate axes.

Default particle radius

  Specifies the display size of particles that have an otherwise unspecified size. This size value is only used for particles for which none of the following applies:

  - The `Radius` property has been set.

  - A non-zero type-specific radius has been set for the particle's type.

  In other words, this parameter provides a fallback value if no display size has been set on a per-particle basis or on a per-type basis.
Rendering quality

  This parameter controls the method used to render the particles. The following modes are available and affect only the rendering of spherical particles:

  Low

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

  Medium

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

  High

    Particles are rendered as true spheres using an OpenGL fragment shader, which computes the ray-sphere intersection for every rendered pixel.

  Automatic

    OVITO automatically switches between the three quality levels above depending on the number of particles to render in the interactive viewports. For less than 4,000 particles, the high-quality method is used. For more than 400,000 particles, the lowest quality mode is used. Irrespective of the particle number, high-quality mode is always used to produce a final output image.