Camera object

You can view your scene through a camera, and render from its point of view.

Placing lights and cameras in the viewer

There are three ways you can place lights and cameras in the scene view. Objects can be moved once they are placed by either dragging them in the scene view or changing the values in the parameter editor.

To... Do this

Place lights and cameras in a specific location in the scene view

  1. Click the desired light or camera from the Lights and Cameras tab.

  2. Move the cursor into the scene view.

    You can hold Alt to detach the shape from the construction plane.

  3. Click to place the light or camera anywhere in the scene view.

Place lights and cameras at the origin

  1. Click the desired light or camera from the Lights and Cameras tab.

  2. Move your cursor into the scene view and press Enter to place the shape at the origin.

Place a light or camera by looking through it

  1. Ctrl click the desired light or camera from the Lights and Cameras tab.

  2. Use the handles or edit the values in the parameter editor to move the light or camera to the desired location in the scene view.

When looking through the camera there are handles on the sides of the scene view which allows you to orient and crop.

Handles

Clicking on lights and cameras in the scene view gives you more camera and light manipulator handle options. The two that are unique to lighting are the cone handle and the frustum handle. The two that are unique to cameras are the focus handle and the frustum handle.

Cone handle

Allows you to control the delta and cone angle.

Frustum handle

Allows you to set the near and far clipping planes and the focal length.

Focus handle

Allows you to control the depth map focus.

Use the view keys to move a light or camera

  1. Look through a light or camera as described above. You can also choose a light or camera to look through once it is created by choosing it in the camera menu.

  2. Lock the light or camera to the view by clicking the Lock camera/light to the view button, which is located on the toolbar on the right side of the view. You can also lock the light or camera to view by by turning on Tie Camera (or Light) to View in the camera menu.

  3. Use the tumble, track, and dolly keys to move the light or camera.

  4. Unlock the light or camera to place it.

Make a light or camera look at an object

  1. Create an object.

  2. Create a light or camera.

  3. Click Look At on the Modify shelf.

  4. Select the object to look at and press Enter .

You can also make a light or camera look at an object by setting it on the Lookat Options tab on the Transform tab of the parameter editor.

Parameters

Transform

Keep Position When Parenting

When the object is re-parented, maintain its current world position by changing the object’s transform parameters.

Pre-transform menu

This menu contains options for manipulating the pre-transform values. The pre-transform is an internal transform that is applied prior to the regular transform parameters. This allows you to change the frame of reference for the translate, rotate, scale parameter values below without changing the overall transform.

Clean Transform

This reverts the translate, rotate, scale parameters to their default values while maintaining the same overall transform.

Clean Translates

This sets the translate parameter to (0, 0, 0) while maintaining the same overall transform.

Clean Rotates

This sets the rotate parameter to (0, 0, 0) while maintaining the same overall transform.

Clean Scales

This sets the scale parameter to (1, 1, 1) while maintaining the same overall transform.

Extract Pre-transform

This removes the pre-transform by setting the translate, rotate, and scale parameters in order to maintain the same overall transform. Note that if there were shears in the pre-transform, it can not be completely removed.

Reset Pre-transform

This completely removes the pre-transform without changing any parameters. This will change the overall transform of the object if there are any non-default values in the translate, rotate, and scale parameters.

Transform Order

The left menu chooses the order in which transforms are applied (for example, scale, then rotate, then translate). This can change the position and orientation of the object, in the same way that going a block and turning east takes you to a different place than turning east and then going a block.

The right menu chooses the order in which to rotate around the X, Y, and Z axes. Certain orders can make character joint transforms easier to use, depending on the character.

Translate

Translation along XYZ axes.

Rotation

Degrees rotation about XYZ axes.

Pivot

Local origin of the object. See also setting the pivot point .

Look At

Object to point to. Constrains an object so its -Z axis always points at another object’s origin.

Look At Up Vector

When specifying a look at, it is possible to specify an up vector for the look at. This controls the roll of this object when looking at the look at object.

Don’t Use Up Vector

Use this option if the look at object does not pass through the Y axis of this object.

Use Up Vector

This precisely defines the direction of the Y axis of this object while looking. The up vector specified should not be parallel to the look at direction. The value used is specified by the Orient Up Vector parameter below.

Use Quaternions

Quaternions are a mathematical representation of a 3D rotation. This method finds the most efficient means of moving from one point to another on a sphere.

Path Object

A reference to the curve node or object you want this object to follow.

Roll

The orientation of the object around the path.

Position

The position of the object along the path. 0.0 means at the beginning of the path, and 1.0 means the end. The integer portion of the position is used as the primitive number inside the geometry while the fractional part indicates the u value on the primitive.

If the primitive number does not exist, then it is wrapped back to the beginning. So for numbers greater than 1.0 in a path object that only have a single primitive, it wraps around to the beginning again. You can easily animate something moving around a circular track simply by continuously increasing the position value.

Keyframe this value to animate the object moving along the path.

Note

The Follow Path tool on the shelf automatically sets keyframes on this parameter that you may want to edit or replace.

The Parameterization option controls how position values between 0 and 1 correspond to knots on the path curve.

Parameterization

Controls how the Position parameter is translated into a point on the path curve. Use Arc-length (the default) to interpolate the position values evenly along the physical length of the curve.

Use Uniform to distribute the position values between the knots of the curve. This lets you slow down the object at certain points by bunching up knots in the path curve. However, it is much more convenient to simply edit the animation curve to control the speed of the object along the path.

Orient Along Path

Orient the object according to the path’s curvature.

Orient Up Vector

The direction vector of the object’s Y axis to orient with.

Auto-Bank factor

Controls automatic banking of the object as it turns corners. Set this to 0 to turn automatic banking off.

Render

Display

Whether or not this object is displayed. Turn on the checkbox to have Houdini use this parameter, then set the value to 0 to hide the object, or 1 to show the object. If the checkbox is off, Houdini ignores the value.

Set Wireframe Color

Use the specified wireframe color

Wireframe Color

The display color of the object

Viewport Selecting Enabled

Object is capable of being picked in viewport.

Select Script

Script to run when the object is picked in the viewport. See select scripts .

Cache Object Transform

Caches object transforms once Houdini calculates them. This is especially useful for objects whose world space position is expensive to calculate (such as Sticky objects), and objects at the end of long parenting chains (such as Bones). This option is turned on by default for Sticky and Bone objects.

See OBJ cache preferences for how to control the size of the object transform cache.

View

Icon Scale

Scales the viewport geometry. This parameter is only for display purposes.

Resolution

The output resolution in pixels. Standard presets are available via the pull down menu to the right of the parameter.

Pixel Aspect Ratio

Pixel aspect ratio (width/height) of the intended display device.

Projection

Type of camera projection used for rendering.

Perspective

This simulates the classic pinhole camera where camera rays emanate from a common camera origin through a flat camera plane.

Orthographic

This uses parallel camera rays that are orthogonal to the (flat) camera plane. The width of the view volume is determined by the Ortho Width parameter below.

Polar (panoramic)

This projection uses a spherical camera plane for rendering.

Cylindrical (panoramic)

This projection uses a cylindrical camera plane for rendering.
Note

Selecting Polar or Cylindrical will automatically switch the Rendering Engine (on the output driver) to Ray Tracing, as it is impossible to render a polar or cylindrical projection with micropolygon rendering.

Focal Length

Camera focal length (zoom).

Focal Units

The units used for the focal length.

Aperture

Width of the visible field.

Ortho Width

Width of orthographic view volume when using Projection is set to Orthographic.

Near Clipping

Position of near clipping plane.

Far Clipping

Position of far clipping plane.

Screen Window X/Y

Define the center of the window during the rendering process.

Screen Window Size

Scale for expanding the cropped area specified by the Crop parameters.

Left/Right/Bottom/Top Crop

Defines the cropping area in terms of the camera’s viewing area margins.

Sampling

Shutter Time

The portion of the frame interval that the camera shutter is open. Used to determine motion blur. [0,1]

Focus Distance

The lens focal distance and distance from the camera at which objects will be in focus. This is only used when rendering using depth of field. Objects outside this distance will be blurred.

F-Stop

Lens fstop. This is only used when rendering using depth of field. Determines blurriness of depth of field effects.

Bokeh

Filter kernel used in depth of field rendering.

radial

Use a gaussian filter kernel (highest quality)

box

Use a box filter kernal

null

Do not filter