Show the markers on all visible components.

Only show the markers on selected components (points, primitives, vertices).

Only show the markers near the mouse pointer.

Only show the marker on the component (point, primitive, vertex) under the mouse pointer.

Draw small dots showing the point locations.

Draw the point number next to the point location. Point numbers start at 0.

Draw the point normal direction as a small line from the point location. You can change the line length using the Normal scale option on the Guides tab.

If a point does not have a normal attribute, Houdini draws a generated normal (as used by the viewport and Mantra), in a dimmer color.

Draw each point’s UV texture coordinates next to the point location.

Draw each point’s 3D coordinates next to the point location. Drawing three decimal numbers for each point can clutter the screen quickly, so you might want to use the visibility menu for this option.

Draw a trail line from the current point position back to where it was in the previous frame. This information is taken from the point’s v (velocity) vector attribute. You can scale the trail length using the Vector scale option on the Guides tab.

Draw the number of overlapping points when multiple points overlap on the screen (for example, if three points overlap, draws a 3).

This is in screen space, so it’s most useful when the geometry you're looking at occupies a lot of the viewer. If the geometry is small/far away, you’ll get a lot of useless overlap readings.

Don’t turn this on for all geometry in the scene. It works best on the display geometry, or only the selected geometry.

Draw lines representing the limits of NURBS, Bézier surfaces, curves, and metaballs.

It can be useful to display hulls in place of the actual geometry when extremely large numbers of these types of geometry fill the screen, to reduce clutter and speed up the display.

Draw the primitive number next to the primitive. Primitive numbers start at 0.

Draw the primitive normal direction as a small line from the primitive’s location (for primitives that have normals). You can change the line length using the Normal scale option on the Guides tab.

Draw edit points on NURBS and Bézier curves/surfaces.

Draw profile (trim) curves on NURBS surfaces.

Draw the profile curve number next to the start of profile (trim) curves. Profile curve numbers start at 0.

Tint backfacing polygons so that they are easily distinguishable from frontfacing polygons.

Draw small boxes showing the vertex locations. Draws the vertices slightly offset inward on the polygon face so you can tell the vertices apart from each other and the point. Unselected vertices are hollow, and selected vertices are filled.

Draw the vertex number next to the vertex location. Draws numbers for vertices of different polygons in slightly different shades, to make them easier to tell apart.

Draw the vertex normal direction (if the vertex has a normal attribute) as a small line from the vertex marker’s location. Draws normals for vertices of different polygons in slightly different shades, to make them easier to tell apart. You can change the line length using the Normal scale option on the Guides tab.

Draw each vertex’s UV texture coordinates next to the vertex marker location.

In UV viewports, change the fill color of back-facing polygons to make it easy to tell them apart from front-facing polygons.

In UV viewports, change the fill color of regions where multiple primitives overlap.

The shading mode for surfaces in the current category. For example, you can have scene geometry drawn as smooth shaded, and templated geometry drawn as wireframe.

Ignore the viewport shading mode control for surfaces in the current category.

For example, this is on by default for templated geometry, so (for example) changing the viewport shading mode between shaded and wireframe does not change the look of templated geometry.

Draw curves/surfaces with a grayed-out, less prominent look.

Ignore any color (Cd attribute) or any texture on curves/surfaces. Uses the default wireframe colors and the default material. This generally used for “templated” geometry. You can change the defaults on the Material tab.

Show the wireframe of any geometry hidden behind other surfaces.

Allow lighting to affect the look of geometry in the current category. This overrides the viewport’s lighting setting.

Show boundaries of meshes (non-shared edges).

Show boundaries of UV texture coordinates on meshes (UV island edges).

The name of the geometry attribute used for UV boundaries and UV map visualization.

When enabled, use this texture map for visualizing UVs. This will only affect geometry with a UV attribute and no material assignment (though turning materials off will remove the assignment, and allow this texture visualization to be seen).

Scale the UV coordinates by this value when visualizing UVs with a UV Map. This does not affect textured materials.

Automatically detects the attribute type in a UV texture editor viewport.

The attribute type for UV viewports, when Auto Detect Attribute Type is off.

Draw timing information (frames per second (FPS), draw time, and elapsed time), in the corner of the viewer. This can be useful for testing scene performance. You should use the FPS as a reference for animation speed, and the elapsed time when comparing playback times.

The FPS display is limited to a maximum of 120, to avoid showing extremely high and misleading values.

Display render time and progress as reported by the current renderer. Only supported in LOPs.

Display render statistics reported by the current renderer, as specified in usd_renderers.py. Only supported in LOPs.

Draw information about the current scene/model (for example, total number of polygons and number of selected polygons) in the bottom-right corner of the viewer.

Draw selected objects with a highlighted wireframe or outline. If you turn this off, selected objects will look exactly the same as unselected objects. This only applies to object-level selection.

Fill selected components with the highlight color. For example, selected faces will be filled with the selection color. When this is off, Houdini only highlights the wireframe, allowing you to see the shading/texture of selected faces. This setting affects all wire-over modes: Wireframe Ghost, Hidden Line Invisible, Hidden Line Ghost, Flat Wire Shaded, and Smooth Wire Shaded. Pure Wireframe is not affected by this setting as it does not display faces, nor is Flat Shaded or Smooth Shaded, both of which always fill the face. This is only available when viewing a SOP.

Draw the primitive to which the selected components “belong” in a secondary highlight color. This may be useful for NURBS and Bézier surfaces, where it might not be clear which surface a control point out in space belongs to. This is only available when viewing a SOP.

Indicate selected LOP primitives by shading them with a solid fill or drawing an outline around them. This is only available when viewing LOPs.

Automatically scale all guide sizes according to the monitor’s reported DPI. You can turn this off to manually scale all guide sizes (this does not affect the Guide font size).

Scales the length of normal markers.

Scales the length of vector direction markers, such as velocity trails.

Scales the size of location “dot” markers, such as points.

Scales the size of the gnomon drawn at the world origin. You can turn it off completely using the Origin gnomon checkbox on this tab.

Scales the size of the gnomon drawn in the bottom left corner of the view. You can turn it off completely using the Floating gnomon checkbox on this tab.

The relative size of marker text drawn in the view, such as point numbers.

Controls the amount of highlighting when the mouse pointer is over a handle. “Off” does no highlighting. “Small” brightens a handle when the mouse is over it. “Normal” draws a prominent glow around a handle when the mouse is over it.

Vertex markers and normals are inset into the polygon so they can be selected independently when part of a seamless mesh. When disabled, the markers and normals are placed at the actual vertex, potentially overlapping.

Increases or decreases the display resolution of metaballs, NURBS, and Bézier surfaces.

Fixes concave polygons by tessellating them to triangles so they appear the correct shape. There are two options for determining when to redo the convexing:

The maximum polygon count that subdivision can produce when subdivision is enabled for that object. If exceeded, try the next subdivision level down until the resulting polygon count is acceptable, which may be no subdivision at all. This is expressed in millions of polygons. Increasing this limit may cause very long updates for subdivision objects and long draw times.

Controls the display quality of volumes in the viewer.

Enabling HDR Rendering will remove any banding artifacts from volumes.

Controls how the viewport interpolates volume values when drawing fog volumes.

Intensity of self-shadowing for fog volumes from ambient light sources. This default is overridden by the volvis_ambientshadows detail attribute. Note that the default headlight is treated as an ambient source by fog volumes.

The thickness (in pixels) of wireframe lines. The range of available values depends on the OpenGL driver.

Opacity of the wireframe in “Shaded wireframe” mode, from 0 (transparent) to 1 (opaque). You may want to turn this down to keep surface color/texture visible underneath a dense wireframe.

The visibility of “interior” wireframes (such as inside tetrahedrons), from 0 (not visible) to 1 (drawn the same as exterior wireframe).

Apply lighting to curves. This is useful when using curves to represent hair.

Lets you select surfaces in wireframe mode by clicking where the surface would be if it was drawn.

Show polygon outlines on meshes in packed geometry when drawing a wire-over-shaded mode. Disabling this hides the outlines on packed geometry, making meshes appear as a single shape, which packed geometry technically is.

How Houdini draws particles and disconnected points.

If particles have sprite attributes (see the Sprite node), draw the sprite image at the particle location.

The size (in pixels) of particle and unconnected points, when Display particles is “Point”.

The size (in Houdini units), of the filled circles, when Display particles is “Disc”.

When Display particles is “Disc” or “Sprite”, this orients the discs with the particle’s normal. If the particle doesn’t have a normal, it uses the particle’s velocity.

The minimum and maximum display size of a sprite texture.

Use OpenGL point instancing to replace the points of Instance objects (and any other objects with the proper instancing properties) with the instanced geometry in the viewport. See instancing for more information.

To increase viewport performance, you can lower the percentage of the total number of points that are replaced with referenced geometry. For example, setting it to 50 will only replace half the points with the instanced geometry. The other half will instance the Stand-in geometry.

What to draw for points that can’t be replaced with the referenced geometry (when the Point Instancing percentage is less than 100, or the number of points to instance exceeds the Instancing Limit). “Display off” draws nothing, “Location marker” draws a dot, and “Bounding box” draws the bounding box of the referenced geometry.

The type of normal to generate when no normals exist on the geometry.

The angle, in degrees, at which the surface stops smoothly shading and instead creates a cusp. The angle is measured between neighboring polygons. This has no effect if Point Normals are auto-generated.

The upper limit, in millions of polygons, where normal auto-generation will switch from Vertex Normals to Point Normals. Large models often take too long to generate vertex normals and display speed is affected as well. In this case, it is better to use a Normal SOP to generate vertex normals on the geometry if vertex normals are desired, rather than have the viewport continually recalculate them.

If tangent-space normal maps are used in a material, the viewer requires that tangents are present. It can auto-generate them if they don’t exist in the geometry. The material may have artifacts if the tangents used to generate the tangent space normal map don’t match the tangents generated by the viewer method.

Smooths edges of lines and polygons in the viewport. Increasing this increases the amount of framebuffer memory Houdini uses. Only use modes higher than 4× if your graphics card has 2GB of VRAM or more. Modes above 16× are significantly slower and give diminishing returns on quality, so it is best to find a “good enough” setting rather than maxing this value.

Produces higher quality render of volumes and transparency. This doubles the amount of framebuffer memory Houdini uses. When this is on, flipbooks will contain HDR images.

You can use this with a LUT (in the Color Correction section) to view super-white values.

Draw objects with the X-ray flag (bones and nulls) as wireframes when they're behind solid surfaces.

Controls the strength of the X-Ray wireframe. Values less than 1 will dim the lines, and values greater than 1 will widen the lines.

Draw axis and pivot points at the object origin of objects with the Display Origin flag.

Show the viewport options menu (titled with the viewport name) in the top right corner of the viewport.

Name for the viewport, for example persp1 for a perspective viewport.

Show the camera options menu (titled with the name of the camera the view is looking through) in the top right corner of the viewport. If the view is not locked to a camera, the menu is titled “no cam”.

Show additional text information about the current state, if any.

Show icon badges beside the viewport menus to indicate various viewport settings or state that is relevant to the user.

Geometry objects are drawn with onion skins if their Onion Skinning parameter is set. This is a global toggle to quickly disable all onion skinning in the scene, without the need to turn off each individual objects' Onion Skinning parameter.

Shows a number of skins for frames in the future, before the action at the current frame has taken place. These skins can be tinted with the color swatch to differentiate them from the past frames.

Shows a number of skins for frames in the past, after the action at the current frame has taken place. These skins can be tinted with the color swatch to differentiate them from the future frames.

The number of frames between skins. A frame increment of 1 will show tightly packed frames, whereas higher increments will skip frames. Fast motions are easier to see with a small frame increment, while slow motions are easier to see with a larger frame increment.

Each skin can be drawn with transparency so that the main geometry and other skins can be seen more easily. A value of 1 makes the skins opaque, and values closer to zero make the skins more faint.

Applies gamma correction to user geometry in the viewport. This does not affect guides, handles, and other interface elements.

Applies a Lookup Table (LUT) to the use geometry, after gamma is applied.

Apply the gamma correction and LUT to the background image as well as the user geometry.

Restore the current viewport layout to its default layout.

What kind of view the viewport shows – “Perspective”, “UV”, or an orthographic view direction such as “Front”.

Set the horizontal field of view, in degrees, of the default viewport camera. This has no effect when the viewport is looking though a camera.

Sets the ratio of width divided by height (eg. 16:9 would be 1.777). This only has an effect when the viewport isn’t looking through a camera.

Sets the center of the crop region, in 0..1 screen space. The default is the center of the viewport (0.5, 0.5).

Sets the size of the crop region, in 0..1 screen space. The default is (1,1) - no scale.

The opacity of the mask showing which areas of the view will not be rendered (when looking through a camera), from 0 (fully transparent) to 1 (full opacity black).

For example, a very low value would display a transparent mask; a medium value would display a gray mask; and a high value would display a black mask.

The display mode of stereoscopic images in MPlay. You can use passive polarization glasses to view the images in horizontal interlace mode.

Which clipping planes are automatically adjusted when you home the viewport. If you set explicit near and/or far clipping planes, this lets you prevent them from being changed by homing.

The nearest distance to and the farthest distance from the view camera to draw geometry. That is, geometry nearer to the view camera than the near clipping plane, or farther away than the far clipping plane, is not visible in the view.

Due to GPU Z-buffering issues, the far/near ratio should never be more than one million. If you enter a larger range is selected, Houdini will simply move the near clip plane out until the far/near ratio is one million.

When homing, treat geometry smaller than this size as if it was this size (in Houdini units). This prevents huge camera moves when you home a scene that is very small (such as a single point).

Turn this on and set the view to look through a camera to simulate depth of field in the OpenGL scene view. You can control the range that is in-focus using the camera’s F-stop parameter (the F-stop must be non-zero to get depth of field).

This effect works by blurring the OpenGL rendered pixels, so it is quite fast but can give strange results in areas with lots of blurring, since it is a post-process that can only work with the available pixels. So for example it can’t simulate light blurring out from behind objects.

Simulate Bokeh flares for bright points in out-of-focus areas. This is only available if the GPU and operating system support OpenGL 4.4.

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.

Show the current camera’s foreground image, if any. The foreground image is specified as a parameter on the Camera object, and it can be an image file or a COP reference. Foreground images are displayed over the regular geometry.

When enabled, use the specified plane to adjust the depth of the image so it z-composites into the scene. The image should be rendered from the same camera. This can be used as a standin for a huge number of objects that would otherwise take a lot of memory and time to draw. The plane must be found in the image file or COP as an AOV.

Allows for multiple representations of depth.

Reduce this to make the foreground image more transparent so that the geometry behind it can be seen.

How to show lighting in the viewer.

OpenGL only: In the High Quality Lighting modes, the Flat shading modes are not available. Smooth shading is always used. The High Quality Lighting modes only work with a perspective view. Orthographic view mode will use normal quality lighting instead.

Show the effect of direct lighting on surfaces.

Show the effect of ambient lighting on surfaces.

Show the effect of specular reflection on surfaces.

Show the effect of light emission (glow) from surfaces.

Improve shading performance of lighting by limiting the number of lights used. The lights with the highest intensity are used.

The number of samples to use when rendering area and environment lights when Quality is “High Quality”. Higher numbers produce more accurate results, with slightly lower performance.

Improve shading performance of “High Quality” lighting by limiting the total number of light samples across all lights.

Drops the number of samples used in HQ Lighting to improve performance when interacting with the viewer, which includes tumbling, moving handles, or playing the timeline. This may result in slightly different lighting while interacting with the viewer.

The brightness of the headlight when Lighting is “Headlight”.

The headlight is treated as a distant light with parallel rays. This sets the direction of the headlight rays, relative to the camera. The default is over, behind, and to the right of the camera.

Show specular highlights caused by the headlight, when Lighting is “Headlight”. When this is off, the headlight casts diffuse light only.

Do an ambient occlusion pass after lighting to increase contrast on local features and give a better sense of depth to models.

Enables screen-space ambient occlusion, when Lighting is “High quality”. This shadows objects based on the amount of ambient light that could reach a surface. Areas in corners and sunken areas will be shadowed. Turning this on decreases display performance.

The numeric value increases the quality and range of effect of the occlusion, softening the overall effect.

Controls the quality of shadow visualization in the view. Higher levels give better shadow approximations, especially for area and environment lights, but decrease display performance.

Correct for shadow map artifacts, which look like moiré patterns or “shadow acne” on surfaces. In general, increase the first value to fix self-shadowing artifacts on surfaces that are edge-on to the light, and the second value for surfaces perpendicular to the direction of the light.

Controls the resolution of the shadow maps, based on the individual light object’s settings, or using a global setting for all lights. 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.

Memory limit for shadowmap generation.

Time limit for shadowmap generation. Multiple redraws are queued to show the partially updated scene when this limit is exceeded.

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.

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.

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.

Color objects in the view using their assigned materials. When this is off, Houdini draws objects using the Default Diffuse, Default Specular, Default Ambient, and Default Emission below.

The Cd attribute on geometry is multiplied into the material color when this is on.

Draw objects with per-pixel alpha, texture maps with alpha, or material transparency using alpha blending. When this is off, Houdini draws any pixels with non-zero alpha as opaque.

Draw geometry with materials that have a displacement map as displaced surfaces using adaptive tessellation. This may cause a reduction in performance, which can be adjusted with the Level slider.

OpenGL 4.0 is required for this feature. This option will be disabled if OpenGL 4.0 is not available.

Diffuse color to use for surfaces that have no material.

Specular color to use for surfaces that have no material.

Ambient color to use for surfaces that have no material.

Emission color for surfaces that have no material. This produces a constant shading effect.

Diffuse roughness to use for surfaces that have no material.

Specular roughness to use for surfaces that have no material.

The file path to a Material Capture (MatCap) texture for the MatCap default material. A MatCap texture encodes lighting and shading information, much like a lat-long environment map.

The intensity multiplier for a MatCap texture.

Evaluate and apply material assignments and overrides based on material stylesheets affecting the object and geometry. When disabled, the effects of any stylesheets will not be scene but the scene may update and draw faster.

Allow material stylesheets to be evaluated on a per-primitive basis when applied to geometry. When off, only the object assignment is used.

Allow material stylesheets to be applied to portions of geometry that is packed inside a packed primitive. When off, only the packed primitive assignment or object assignment will be used.

Allow material overrides from material stylesheets or the material_override attribute. When off, material overrides are ignored.

The maximum number of materials and material variants allowed to be assigned to a single object by material stylesheets, overrides, or shop_materialpath attribute. When this is exceeded, the remaining primitives will be assigned either the default material, object material, or the packed primitive material. A note is made of this in the viewport information button on the right toolbar.

Limit when material assignments are updated, as this can be expensive.

Update materials when they change. When disabled, changes to the materials themselves will not be reflected in the viewport unless Update Materials is pressed.

Forcibly update all material assignments, stylesheets, and materials. This is useful for stylesheets with external script files when those files change (they are not monitored for changes), or when automatic updates have been disabled.

Draw a simple atmospheric fog effect in the viewport, essentially blending a tint color with each pixel based on how distant the pixel is from the camera. The effect does not correspond to any volume object (it’s uniform across the entire scene space), and is not affected by lighting.

This effect post-processes the OpenGL rendered pixels, so it is very fast, and can give increased depth cues. It is best used with low Density levels, because higher levels can reveal the “fake-ness” of the effect.

You can also simulate a sun burning through the fog, which can create a nice hazy artistic effect. Of course the “sun” does not actually contribute light to the scene, since this is a post-process effect.

Tints the generated fog. You can use this to look it look more like smog, haze, or dust.

Controls how visible the uniform fog is (how much the fog color blends into the rendered pixels). You should keep this small (below 50) to avoid washing out the entire scene. This value is scale-dependent, so if you are working with, for example, a centimeter-scale scene you will need to adjust this value.

An additional scale factor on the final fog result to make it heavier (greater than 1.0) or lighter (less than 1.0).

The distances at which the fog begins and ends, in Houdini distance units from the camera. All depths beyond the end are clamped to the end depth. Any distance before the fog start does not have any 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.

Anything beyond the depth clip value not have fog applied. This is useful for preventing fog on skyboxes or other image-based background elements.

Enable simple lighting of uniform fog based on a distant light in the scene. The distant light’s color will tint the fog in that direction. Adjust the slider to control the size of the light bloom around the sun (scattering). Very small values produce a crisp sun disc (0.01), whereas larger values will tint most of fog in that direction (above 1). This requires a distant light in the scene. In case more than one active distant light exists, the brightest one is chosen.

For uniform fog with the Sun enabled, this provides an additional intensity adjustment on the distant light’s color.

Simulates volumetric lighting/shadows through a single volume, aligned to the camera frustum. Where uniform fog is a post-processing pixel effect, volumetric fog simulates an actual volume, with the lights and geometry in the scene creating light rays and shadow shafts.

You must have high quality lighting turned on in the viewer to see this effect.

This is only available if the GPU and operating system support OpenGL 4.4.

Tints the volume. You can use this to look it look more like smog, haze, or dust.

Controls how dense the fog volume is. This is not the same as the density setting on a volume object (where 1 would be opaque). Instead it has a similar range to Density for uniform fog, generally from 1 to 100 for meter-scale scenes. This value is scale-dependent, so if you are working with, for example, a centimeter-scale scene you will need to adjust this value.

This controls the resolution of the volume. Low quality is fast but coarse, Medium is a balance between performance and quality, and High and Very High quality are more accurate but much slower.

An additional scale factor on the final fog result to make it heavier (greater than 1.0) or lighter (less than 1.0).

The portion of the view frustum that will have lit fog, in Houdini distance units from the camera. Set this so the depth range is as tight as possible to the lights you want to light the fog. (This is to avoid wasting precision on areas without lights.)

This effect uses the (rendered) light intensity of the scene lights by default. However, physically correct lighting may look too subtle or too blown out in OpenGL. This is a global scale on the intensity of the scene lights. The view will also look for a gl_fogintensity property on each light. If that property exists, it is used instead of this value.

The default for this scale is 1. It may be useful to set this to 0, so only the lights you specifically add the gl_fogintensity property to will affect the 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.

To reduce bright light blooms while still keeping god rays visible, lower the first value.

You can set this value per-light by adding the gl_fogscattering property to the light node.

Bloom is a simple effect that mimics subtle atmospheric or lens effects around bright spots in the scene. Adjust the slider to modify 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 brighter than this threshold will begin to bloom (white being 1.0). Increasing this value will produce less blooming in the scene.

The path to a node which has Fog Properties that override the settings above (Uniform Fog, Volumetric Fog, Bloom). This lets you switch between override nodes to switch between different looks. Node parameters can also be animated, unlike display options. If a property doesn’t exist as a parameter on the node then it is taken from the display options instead.

Show a grid in orthographic viewports.

The distance in X, Y, and Z between the grid origin and the world-space origin.

The horizontal and vertical distance between grid lines, in Houdini units.

Draw every ‹n›th grid line thicker. Set this to 0 to not draw thicker lines.

Show a grid using the given Grid spacing.

The distance between grid lines, in UV coordinate values.

Show a pixel grid over the texture image, using the Grid pixel spacing and Grid pixel offset.

The placement and size of the pixel grid, in pixels. You can use decimal values, for example an offset of 0.5 to snap to pixel centers.

Don’t show the grid outside the boundaries of the image.

Draw guide lines representing the boundary around the 0-1 tiling of the image.

Draw the image as a 360 degree environment map rather than a 2D image. The image should be a lat-long map or a 6-face cube map.

Automatically scale the image to fit the image inside the viewport (not available for UV viewports). When this option is off, you can use the Image Offset and Image Scale controls to place and scale the image manually.

Controls how the image should be fit to the viewport. This option is ignored when Auto-Place Image is off.

Manually control the placement and scale of the background image in the viewport, when Auto Place Image is off. A scale of 1 uses the original image size. A scale of 0.5 would make the image half size. Not available for UV viewports.

The strength of transparency of the background image or video. Lower values increase the transparency and higher values decrease the transparency.

The default value is 1, which makes the background image or video fully opaque.

The brightness of the background image or video. Lower values darken the image or video and higher values lighten them.

The default value is 1, which uses the background image or video’s original brightness.

Controls the fidelity of the background image by downscaling it. Lower values give lower quality background images but use less memory.

The first and last frames of the background video, which determine the video’s range. Click Trim to open a video preview to select the range.

The default values are 1, 1. Click Reset to reset this parameter back to its default values.

The frame on the Playbar when the background video appears and starts playing.

The default value is 10.

The speed that the background video plays during playback.

The default value is 1.

The playback speed of the background video. The parameter maps this imported value, or an updated value that you set, to the scene frame rate (the frames per second set in the Global Animation Options window) so the video plays back at that specific frame rate.

For example, if this parameter is 1 and the Global Animation Options' FPS parameter is 24, the video advances by one frame every 24 scene frames during playback. Similarly, if this parameter is 60 and the Global Animation Options' FPS parameter is 30, the video advances by two frames for every scene frame during playback.

The default value is 24. Click Reset to reset this parameter back to its default value.

The color space to apply to the background video.

The default value is sRGB - Texture.

Show surface textures in the view. Turning this off can increase display performance.

Displays all layers of multi-layered textures. Turning this off will only display the first texture, but can increase display performance.

Show spotlight projection maps in the view (see the Projector map parameter on the light object). This adds one drawing pass per spotlight in the scene. Even when this option is on, the projected maps will not affect transparent objects or volumes. This option only works when using High Quality lighting.

Increase the quality of displayed textures by producing a mipmap for enhanced filtering. When this option is off, textured objects will sparkle when viewed at a smaller scale. This option causes textures to use 50% more memory on the graphics card.

Higher values increase the quality of textured objects when a surface is nearly parallel to the view direction. Increasing this will slightly decrease display performance.

The maximum amount of memory to use for textures, both 2D and 3D (in megabytes).

OpenGL always stores textures in main memory and may swap them to and from the graphics card, so this setting can affect the amount of memory available to Houdini. The maximum texture cache size is limited on 32 bit computers.

Remove all currently unused textures from the cache and force an update of all textures that are in use.

Checks all textures with a file source to see if they are updated and reload them if they are.

The maximum amount of memory that a single texture can consume (in MiB). Even with a large amount of available VRAM, very large textures can have performance issues. This option is automatically set based on the detected VRAM (where possible), from 64MiB to 256MiB. It is not saved to .hip files.

Displays the amount of texture cache currently in use. To flush the cache, use Render ▸ Update Textures from the main menu.

When drawing the viewport, if the total size of all textures used is greater than the texture cache size, texture thrashing will result. This causes severe performance degradation as textures are continually reloaded and deleted on every redraw. If this option is on, Houdini detects this situation and on the next redraw scales textures to a size that will fit in the cache.

Apply dynamic texture scaling to 2D textures. The box next to the option shows the current dynamic scale.

Apply dynamic texture scaling to 3D textures. The box next to the option shows the current dynamic scale.

Limit the size of 2D textures to the specified size (if it is less than the maximum size allowed by the graphics card). When this option is off, texture sizes are only limited to the maximum size supported by the graphics card. This option can reduce graphics card memory usage and improve performance, at the expense of decreasing display quality of large textures.

This only affects new textures and will not cause updates of loaded textures (use Render ▸ Update Textures from the main menu to apply the limit to these textures).

Cube maps are also affected by this size, though it applies to their faces. The maximum size of shadow maps is controlled on the Lights tab.

Show High Dynamic Range texture images. Using HDR images will give better shading on textured surfaces when lighting is on in the view.

Scale all 2D textures to a percentage of their original size. You can use this to quickly improve performance of a highly-textured scene if it is stuttering on redraw.

This scale is applied before the Limit Resolution option.

Limit the resolution of 3D textures, which are often used to represent volumes.

If you need better quality, increase the limit values. Do not turn this off unless you really know what you're doing. Larger 3D textures can use a huge amount of graphics card RAM. High resolution (simulation) volumes can use far more memory than reasonable to display on a graphics card. (When this option is off, volumes are limited to the maximum OpenGL 3D texture size.)

This only affects new 3D textures.

Copy the HDR textures and Scale textures settings from the 2D textures options. When this is off, you can specify separate values for 3D textures below.

(8 bit Compressed is not supported for 3D textures, so if the 2D setting is “8b Compressed”, 3D textures will use 8 bit SDR.)

Show High Dynamic Range color and opacity for volumes and other 3D textures. This can improve the quality of volumes at the expense of performance and graphics memory use.

Scale all 3D textures to a percentage of their original size. This can be useful for displaying extremely large simulated volumes.

This scale is applied before the Limit Resolution option.

Only object names that match this pattern will be visible in the view.

In shaded view modes, do not draw polygons that face away from the camera. This can improve display speed on very heavy polygonal geometry.

For closed (airtight) surfaces, back faces are not visible anyway, but open surfaces often have visible back faces that will disappear when this option is on. For example, if you create a cylinder (without end caps) and look down at it with this option on, only the front half of the cylinder will appear in the view.

Draw the hulls of certain primitives instead of the normal geometry. This applies to NURBS surfaces and curves, Bezier surfaces and curves, metaballs, volumes, and VDBs.

When enabled, replace packed geometry with bounding boxes if the total polygon count of all the packed geometry within the view frustum exceeds the Scene Polygon Limit. Distant packed geometry is replaced with boxes first. This preserves viewport performance for large scene files at the expense of visual quality, making it easier to navigate the scene.

The maximum number of polygons to draw in the scene. When this is exceeded, some packed primitives will be replaced by their bounding boxes until the total number of polygons is under the limit.

Determines whether to use wireframe or shaded bounding boxes when replacing geometry in the scene, or omit them entirely.

Perform a series of optimizations on the packed geometry which make it faster to display. The downside of this is that the wireframe representation will no longer match the original geometry’s topology and it will take slightly longer to initially process the geometry.

When turned on, automatically generates a series of reduced-polygon levels of detail for agent shapes, and swaps them in based on the agent’s distance to the camera. This is done to speed up the display of far-away agents. Each level has half as many polygons as the previous level. The closer the slider is to the Performance side, the more low-polygon levels Houdini generates.

The minimum number of polygons that is generated in a reduced-polygon model when LOD Agent Reduction is turned on. Houdini will not generate any levels of detail with fewer than this many polygons.

The maximum number of reduced levels of detail that is generated when LOD Agent Reduction is turned on. For example, if an agent model has 100000 polygons and Max LOD Levels is 4, Houdini will only generate levels with polygon counts of 50000, 25000, 12500, and 6250. Note that Houdini may not actually generate this many levels if it reaches the Shape Point Cutoff.

The reduced level of detail to use for the display of the closest agents. The default is 0, which uses the original model. A value of 1 uses the first reduced level of detail (with half as many polygons as the original model) even when agents are close to the camera. This lets you quickly and drastically reduce the overall polygon count of a crowd scene for better display performance.

Choose to deform agent models by all bone weights (up to 4), or optimize performance by only deforming based on the highest-weight bone.

Agent rigs can be displayed in several ways when in wireframe mode.

Turns on blend shape deformation for agent shapes at the primary level of detail. This can be turned off to improve performance.

When turned on, and the geometry being displayed contains a packed character scene with animation, the viewport evaluates the scene and displays the deformed characters' shapes. This can be used to view animated characters without entering the animate state or appending an APEX Scene Invoke SOP (see animation workflow for more information).

The viewport also detects geometry that is only deformed by skinning (a sop::bonedeform callback), and performs GPU-accelerated skinning for that geometry (runs the equivalent of sop::bonedeform on the GPU as the geometry is being displayed). If the geometry is modified by other callbacks, the APEX graph’s output geometry is evaluated before it is sent to the GPU to be displayed.