The scene can be fetched from Objects or LOPs.

The camera which defines the scene. In Objects, this is a Camera Object. In LOPs, this is a camera primitive.

The root path for the Object scene. All objects and lights in this object network will be rendered. This only applies to a Object Source.

Which geometry to render in the object, either the SOP with the display or the render flag set. This only applies to an Object Source.

Specifies which objects will be rendered in the scene, if their display flags are also set. The paths can be absolute (\/obj\/geo1) or relative to the scene path (geo1, with a scene path of \/obj). Wildcards can be used (\*, ?), as can the exclusion operator (^). \* \^geo? would render all objects except for those like geo1, geo2, geoN. This only applies to an Object Source.

Specifies that the objects that match the names or patterns of this parameter should always appear in the scene, even if their display flag is off. This only applies to an Object Source.

Do not include objects in the scene if they match the names or patterns given by this parameter. This overrides the Candidate Objects parameter and only applies to an Object Source.

Specifies which lights will be used to light the scene, if they are enabled. The same rules apply to the light mask as

The lights matching the names or patterns of this parameter will always be included, even if they are disabled. This only applies to an Object Source.

Do not include lights in the scene if they match the names or patterns given by this parameter. This overrides both Candidate and Force Lights. This only applies to an Object Source.

The LOP Network or LOP Node that generates the scene from when the Source is LOPs.

Include primitives whose purpose is Render. This only applies to an LOPs Source.

Include primitives whose purpose is Proxy. This only applies to an LOPs Source.

Include primitives whose purpose is Guide. This only applies to an LOPs Source.

Forces all simulation OPs to be reset. This includes DOP Networks, POP SOPs, and other OPs that cache their results.

When enabled, this ROP will appear in the viewport’s render menu.

Normally, the resolution channels on the camera determine the output resolution. Enabling this parameter allows an alternate resolution to be used.

Allows you to override the camera resolution.

The pixel aspect ratio represents the width of a pixel divided by the height of a pixel. It is not the aspect ratio of the image (which is determined by the resolution of the image). This parameter does not affect rendering, it is only used to change how images are displayed, by stretching the pixels by this factor.

Individual frames will be collected into composite sheets when this is enabled. This parameter controls the arrangement of frames in a single sheet. The first value specifies the number of rows, while the second one controls the columns.

Specifies a background image to use, either a file or a COP node reference with op:. The background image is fit to the viewport area if the aspect ratios or size don’t match.

Places a comment in the upper left corner of the image, in addition to any viewport comment on the camera.

The image or device where the resulting image will be rendered. You can set this value to ip which renders the image in MPlay, or you can save it to an image. The following image types are supported: .pic, .tif, .sgi, .pic.gz, .rat, .jpg, .cin, .rta, .bmp, .tga, .rad, .exr, and .png.

Include $F in the file name to insert the frame number. This is necessary when rendering animation. See expressions in file names for more information.

The image format or device for the output image. If you leave this at the default value of Infer from filename, the image format will be selected based on the file extension (eg. .pic will automatically generate a Houdini format image).

The options inside the box that follows are image format-specific.

When turned on, creates intermediate parent directories for output files as needed. Currently only applies to generated scripts, images, and shadow maps.

The number of times the image save will be attempted again before it reports that the save failed.

The type of image to render:

Style of color correction to apply to the output image.

Applies gamma correction to output image. This should usually be left at 1.0.

Applies a LookUp Table (LUT) to the output image, after gamma is applied.

The OpenColorIO colorspace to transform the linear colors produced by the OpenGL render. If empty, leave as linear.

A optional whitespace-separated list of OpenColorIO looks to apply to the color data before converting to the specified colorspace.

Enables high-quality rendering by smoothing jagged edges of lines and polygons. Increasing this setting will proportionately increase the amount of framebuffer memory used. 4× and 8× modes should only be used if the graphics memory installed on the graphics card is 1GiB or higher.

Enables High Dynamic Range (HDR) rendering which produces higher quality results for volumes and transparency. It can also be used in conjunction with a LUT to view superwhite values. If enabled, 16b or 32b floating point HDR images are rendered. Enabling this option doubles or quadruples the framebuffer size.

HDR (16b FP)

Full HDR (32b FP)

When the Camera is a stereo camera, this determines the type of output image(s).

Select a shading mode for all geometry in the scene.

Materials will include textures if enabled.

Area and environment lights are rendered with more accurate representations. Spotlight falloff and ramp-based attenuation are also incorporated into the shading. This mode attempts to closely match the results seen in mantra at the expense of performance.

This shading does not apply to transparent objects if Transparency is enabled. Normal shading is used instead. Additionally, this feature requires Material Shaders.

The number of samples to use when rendering area and environment lights in High Quality Light Shading mode. It is ignored when this mode is not active. Higher numbers produce more accurate results, at a slight performance hit.

Enables light shadowing from those lights which have their Shadow Type parameter set to a shadowing method. This option decreases performance and increases graphics memory use but greatly improves the quality of the viewport display.

Increasing the shadow quality will improve the shadow’s visualization, especially for area and environment lights, with a corresponding performance decrease.

Controls the resolution of the shadow maps. Increasing the shadow map size will reduce the jaggedness of shadow edges and improve fine shadow detail. Larger maps may affect performance and will use more graphics memory.

Enable screen-space ambient occlusion, which shadows objects based on the amount of ambient light that could reach a surface. Areas in corners and sunken areas will receive shadowing. The numeric value increases the quality and range of effect of the occlusion. Enabling this option will slow performance somewhat. High Quality Light Shading and Material Shaders are required for occlusion to work.

Draw objects with per-pixel alpha, texture maps with alpha or material transparency using alpha blending (via an over operation). When off, pixels with non-zero alpha are drawn and zero alpha pixels are discarded. The quality of the transparency can also be selected, with the higher quality options impacting performance.

Enable a motion blur effect, based on the camera’s shutter. The scene is rendered at multiple subframes around the current frame and blended. When enabled, the parameter specifies the number of subframes to render. Increasing the number of subframes improves the image quality, at the expense of a longer render time.

Enable displacement mapping for those materials with a GL Displacement Map parameter. The slider field can be used to increase or decrease the tessellation factor of the displaced surface. OpenGL 4.0 is required for this feature.

Enable reflections using reflection cubemaps. This simulates reflections by rendering the scene to a cubemap with the reflection object removed, at the reflective object’s centroid. Reflective objects are those with a material with a GL Reflect parameter that is greater than zero.

Require that a material have a GL Reflect parameter set to at least this value, otherwise do not consider the material reflective. No reflection cubemaps are generated for objects with non-reflective materials. This can reduce the number of reflection maps generated for very dull materials.

Use a FP16 cubemap to store high-dynamic range reflections. When disabled, an 8b cubemap is used (standard 0-1 color range). HDR reflections look brighter, but use twice the texture memory.

Resolution of the cubemap’s square images, in pixels. Larger maps produce sharper reflections at the expense of increased reflection map generation time and texture memory use.

When enabled, remove all polygons facing away from the camera (as defined by their vertex winding order).

Specify a node path which contains the fog and bloom parameters below. Any parameter that is found will override its parameter on this node. See Fog Properties.

Draw an uniform fog effect in the viewport. Traditional fog applied to geometry based on its distance from the camera. The fog color is blended with the geometry’s color. There is no lighting of the fog, except by the Sun parameter.

Factor that controls how dense the fog is. Small values are generally required to avoid turning the entire scene into a constant fog color. If the scene is in different units than meters (eg centimeters), this will need to be adjusted to keep the same look.

Multiplier on the fog once it has been computed to quickly increase or decrease the fog effect.

Tint the fog with this color. Darker colors will cause the fog to look more like smoke.

For Uniform fog, this is the depths where the fog begins and ends, in unit distance from the camera. All depths beyond the end are clamped to the end depth. Any depth before the fog start do not have fog applied.

For Volumetric fog, this is the portion of the view frustum that will have lit fog, in world units (depth). The depth range should be as tightly bound as possible around the lights which use fog scattering to avoid artifacts.

Maximum distance which uniform is applied. Objects beyond this distance are not affected by fog.

Fog can be limited to areas above or below an elevation in the scene. Fog will begin at the height value, and slowly increase to its density at height plus falloff (or height minus falloff in the Below case). The falloff gives a softer transition from areas with no fog to areas with fog.

Where the fog begins, in world units vertically (Y for Y-up, Z for Z-up).

Gradual transition period starting at the fog height, in world units.

Use a directional light in the scene to do simple lighting when in Uniform mode. The direction and color of the light is used to blend between the fog and light colors. The Light Intensity adjusts the intensity of sun effect. Increasing the bloom increases the amount of fog lit by the sun.

Multiply the distant light intensity by this value if Fog Sun Bloom is enabled.

Draw lit fog using a frustum-aligned volume, lit by the lights in the scene. Many of the parameters are the same as their uniform fog counterparts.

The quality determines the resolution of the lit volume. Low quality is fast but coarse, while High quality is more accurate but much slower. Medium provides a balance between quality and performance.

The default light intensity for all lights that do not have the gl_fogintensity property on them. By default this is 1 (all lights contribute to the lit fog). This can be set to zero so that only lights with gl_fogintensity contribute to the lighting. This setting only affects Volumetric Fog.

The first value controls the intensity of the lit fog when the light ray is parallel to the viewing direction. The second controls the intensity when the light ray is perpendicular to the viewing direction. Bright light blooms can be reduced by reducing the first value while still keeping god rays visible. This setting only affects Volumetric Fog, and can be overridden per-light with gl_fogscattering property on the light node.

Bloom is a simple effect that mimics subtle atmospheric or lens effects around bright spots in the scene.

Modifies the radius of the bloom, which is initially based on the brightness of the pixel being bloomed. This will also affect the intensity of the bloom (larger blooms reduce the overall intensity of the bloom).

Brighten or darken the blooms.

Any pixel brigher than this threshold will begin to bloom. Increasing this value will produce less blooming in the scene.

Enable depth of field effect, based on the camera’s f-stop, aperture, and focus distance.

Simulate Bokeh flares for bright points in out-of-focus areas. This is only available if the GPU and operating system supports OpenGL 4.4 (which excludes MacOS).

Image file to use when Bokeh Effect is From File.

COP path to use when Bokeh Effect is From COP.

Optionally stretches the bokeh shape vertically or horizontally. The default value 1 does not stretch the shape (so if Bokeh is “Circular”, the shape will be a circle). Values greater than 1 stretch the shape horizontally. Values less than 1 stretch the shape vertically.

Artificially increases the brightness of bokeh hot spots. This can also produce more overall bokeh in the scene.

Increases or decreases the display resolution of Metaballs, NURBS, and Bezier surfaces.

The width, in pixels, of wireframe and wire-over-shaded lines.

The amount that wire-over-shaded lines are blended with the underlying shaded surface. Values near zero make these lines very faint, while a value of one draws the line without any blending (opaque). This does not affect pure wireframe, hidden line, or invisible line modes.

The particle representation to use:

Limit 2D Textures (images) to a maximum resolution in one of three ways. Textures are still subject to the Tex Mem Limit memory limitation for a single texture. If a texture exceeds this limit it will be uniformly downscaled to the limit.

Maximum allowable 2D texture width or height.

The maximum allowable bit depth for 2D textures. If a texture’s bit depth exceeds this limit, it will be downcast to the limiting bit depth. If a textures bit depth is less than the limit, it will remain unchanged (ie, not up-converted to the limit bit depth).

Limit 3D Textures (volumes) to a maximum resolution in one of three ways. Textures are still subject to the Tex Mem Limit memory limitation for a single texture. If a texture exceeds this limit it will be uniformly downscaled to meet the limit.

Maximum allowable 3D texture width or height.

The maximum allowable bit depth for 3D textures. If a texture’s bit depth exceeds this limit, it will be downcast to the limiting bit depth. If a textures bit depth is less than the limit, it will remain unchanged (ie, not up-converted to the limit bit depth).

The maximum allowable texture size for a single texture. If the computed texture size exceeds this limit it will be uniformly downscaled to meet this limit. This applies to both 2D and 3D textures, though it more frequently affects tiled textures (UVTile, UDIM). The total memory size of all textures can exceed this size - it only applies to large textures.

The maximum allowable resolution for sprite textures. Sprites larger than this resolution will be downscaled to fit.

The percentage of instances shown when Point Instancing is enabled. Instances not shown will be replaced by the Instancing Standin geometry.

The maximum number of polygons that can be generated when instancing, in millions of polygons. If a single Point Instancing operation exceeds this amount, some of the instances will be replaced by the Instancing Standin geometry.

Geometry to substitute for instances that are culled by either the Instancing Percent or Instancing Limit parameters.

Run this script before any rendering.

Run this script before each frame.

Run this script after each frame.

Run this script after all rendering.