The camera object which defines the scene.

The root path for the scene. All objects and lights in this object network will be rendered.

Which geometry to render in the object, either the SOP with the display or the render flag set.

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.

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.

Do not include objects in the scene if they match the names or patterns given by this parameter. This overrides both Candidate and Force Objects.

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.

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.

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.

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.

Create intermediate parent directories for output files as needed. This 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:

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.

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 depth of field effect, based on the camera’s f-stop, aperture, and focus distance. This is done by rendering the scene multiple times while jittering the camera. When enabled, the parameter specifies the number of times the camera is jittered. Higher values produce a better quality image, at the expense of a longer render time.

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.

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.

This command is run before any rendering is started. It is only run once per render.

This command is run before each frame is rendered.

This command is run after each frame is rendered.

This command is run one time, after all rendering is complete.