# Experimental:Camera COMP

## Summary

The Camera Component is a 3D object that acts like real-world cameras. You view your scene through it and render from their point of view. A Camera Component can be attached or linked to any other 3D Component in a 3D hierarchy.

## Parameters - Xform Page

The Xform parameter page controls the object component's transform in world space.

Transform Order `xord` - - The menu attached to this parameter allows you to specify the order in which the changes to your Component will take place. Changing the Transform order will change where things go much the same way as going a block and turning east gets you to a different place than turning east and then going a block. In matrix math terms, if we use the 'multiply vector on the right' (column vector) convention, a transform order of Scale, Rotate, Translate would be written as `T * R * S * Position`.

• Scale Rotate Translate `srt` -
• Scale Translate Rotate `str` -
• Rotate Scale Translate `rst` -
• Rotate Translate Scale `rts` -
• Translate Scale Rotate `tsr` -
• Translate Rotate Scale `trs` -

Rotate Order `rord` - - The rotational matrix presented when you click on this option allows you to set the transform order for the Component's rotations. As with transform order (above), changing the order in which the Component's rotations take place will alter the Component's final position. A Rotation order of Rx Ry Rz would create the final rotation matrix as follows `R = Rz * Ry * Rx`

• Rx Ry Rz `xyz` - `R = Rz * Ry * Rx`
• Rx Rz Ry `xzy` - `R = Ry * Rz * Rx`
• Ry Rx Rz `yxz` - `R = Rz * Rx * Ry`
• Ry Rz Rx `yzx` - `R = Rx * Rz * Ry`
• Rz Rx Ry `zxy` - `R = Ry * Rx * Rz`
• Rz Ry Rx `zyx` - `R = Rx * Ry * Rz`

Translate `t` - - The three fields allow you to specify the amount of movement along any of the three axes; the amount, in degrees, of rotation around any of the three axes; and a non-uniform scaling along the three axes. As an alternative to entering the values directly into these fields, you can modify the values by manipulating the Component in the Viewport with the Select & Transform state.

• X `tx` -
• Y `ty` -
• Z `tz` -

Rotate `r` - - The three fields allow you to specify the amount of movement along any of the three axes; the amount, in degrees, of rotation around any of the three axes; and a non-uniform scaling along the three axes. As an alternative to entering the values directly into these fields, you can modify the values by manipulating the Component in the Viewport with the Select & Transform state.

• X `rx` -
• Y `ry` -
• Z `rz` -

Scale `s` - - The three fields allow you to specify the amount of movement along any of the three axes; the amount, in degrees, of rotation around any of the three axes; and a non-uniform scaling along the three axes. As an alternative to entering the values directly into these fields, you can modify the values by manipulating the Component in the Viewport with the Select & Transform state.

• X `sx` -
• Y `sy` -
• Z `sz` -

Pivot `p` - - The Pivot point edit fields allow you to define the point about which a Component scales and rotates. Altering the pivot point of a Component produces different results depending on the transformation performed on the Component.

For example, during a scaling operation, if the pivot point of an Component is located at `-1, -1, 0` and you wanted to scale the Component by `0.5` (reduce its size by 50%), the Component would scale toward the pivot point and appear to slide down and to the left.

In the example above, rotations performed on an Component with different pivot points produce very different results.

• X `px` -
• Y `py` -
• Z `pz` -

Uniform Scale `scale` - This field allows you to change the size of an Component uniformly along the three axes.

Note: Scaling a camera's channels is not generally recommended. However, should you decide to do so, the rendered output will match the Viewport as closely as possible when scales are involved.

Constrain To `constrain` - Allows the location of the object to be constrained to any other object whose path is specified in this parameter.

Look At `lookat` - Allows you to orient your Component by naming the Component you would like it to Look At, or point to. Once you have designated this Component to look at, it will continue to face that Component, even if you move it. This is useful if, for instance, you want a camera to follow another Component's movements. The Look At parameter points the Component in question at the other Component's origin.

Tip: To designate a center of interest for the camera that doesn't appear in your scene, create a Null Component and disable its display flag. Then Parent the Camera to the newly created Null Component, and tell the camera to look at this Component using the Look At parameter. You can direct the attention of the camera by moving the Null Component with the Select state. If you want to see both the camera and the Null Component, enable the Null Component's display flag, and use the Select state in an additional Viewport by clicking one of the icons in the top-right corner of the TouchDesigner window.

Look At Up Vector `lookup` - - When specifying a Look At, it is possible to specify an up vector for the lookat. Without using an up vector, it is possible to get poor animation when the lookat Component passes through the Y axis of the target Component.

• Don't Use Up Vector - Use this option if the look at Component does not pass through the Y axis of the target Component.
• Use Up Vector - This precisely defines the rotates on the Component doing the looking. The Up Vector specified should not be parallel to the look at direction. See Up Vector 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.
• Don't use up vector `off` -
• Use up vector `on` -
• Use quaternions `quat` -

Path SOP `pathsop` - Names the SOP that functions as the path you want this Component to move along. For instance, you can name an SOP that provides a spline path for the camera to follow.

Production Tip: For Smooth Motion Along a Path - Having a Component follow an animation path is simple. However, when using a NURBS curve as your path, you might notice that the Component speeds up and slows down unexpectedly as it travels along the path. This is usually because the CVs are spaced unevenly. In such a case, use the Resample SOP to redistribute the CVs so that they are evenly spaced along the curve. A caution however - using a Resample SOP can be slow if you have an animating path curve.

An alternative method is to append a Basis SOP to the path curve and change it to a `Uniform Curve`. This way, your Component will move uniformly down the curve, and there is no need for the Resample SOP and the unnecessary points it generates.

Roll `roll` - Using the angle control you can specify a Component's rotation as it animates along the path.

Position `pos` - This parameter lets you specify the Position of the Component along the path. The values you can enter for this parameter range from `0` to `1`, where `0` equals the starting point and `1` equals the end point of the path. The value slider allows for values as high as `10` for multiple "passes" along the path.

Orient along Path `pathorient` - If this option is selected, the Component will be oriented along the path. The positive Z axis of the Component will be pointing down the path.

Orient Up Vector `up` - - When orienting a Component, the Up Vector is used to determine where the positive Y axis points.

• X `upx` -
• Y `upy` -
• Z `upz` -

Auto-Bank Factor `bank` - The Auto-Bank Factor rolls the Component based on the curvature of the path at its current position. To turn off auto-banking, set the bank scale to `0`.

## Parameters - Pre-Xform Page

The Pre-Xform parameter page applies a transform to the object component the same way connecting another Object as a parent of this node does. The transform is applied to the left of the Xform page's parameters. In terms of matrix math, if we use the 'multiply on the right' (column vector) convention, the equation would be `preXForm * xform * Position`.

Apply Pre-Transform `pxform` - Enables the transformation on this page.

Transform Order `pxord` - - Refer to the documentation on Xform page for more information.

• Scale Rotate Translate `srt` -
• Scale Translate Rotate `str` -
• Rotate Scale Translate `rst` -
• Rotate Translate Scale `rts` -
• Translate Scale Rotate `tsr` -
• Translate Rotate Scale `trs` -

Rotate Order `prord` - - Refer to the documentation on Xform page for more information.

• Rx Ry Rz `xyz` -
• Rx Rz Ry `xzy` -
• Ry Rx Rz `yxz` -
• Ry Rz Rx `yzx` -
• Rz Rx Ry `zxy` -
• Rz Ry Rx `zyx` -

Translate `pt` - - Refer to the documentation on Xform page for more information.

• X `ptx` -
• Y `pty` -
• Z `ptz` -

Rotate `pr` - - Refer to the documentation on Xform page for more information.

• X `prx` -
• Y `pry` -
• Z `prz` -

Scale `ps` - - Refer to the documentation on Xform page for more information.

• X `psx` -
• Y `psy` -
• Z `psz` -

Pivot `pp` - - Refer to the documentation on Xform page for more information.

• X `ppx` -
• Y `ppy` -
• Z `ppz` -

Uniform Scale `pscale` - Refer to the documentation on Xform page for more information.

Reset Transform `preset` - This button will reset this page's transform so it has no translate/rotate/scale.

Commit to Main Transform `pcommit` - This button will copy the transform from this page to the main Xform page, and reset this page's transform.

Xform Matrix/CHOP/DAT `xformmatrixop` - This parameter can be used to transform using a 4x4 matrix directly. For information on ways to specify a matrix directly, refer to the Matrix Parameters page. This transform will be applied after the regular Pre-Transform transformation. That is, it'll be applied in the oder XformMatrix * PreXForm * Position.

## Parameters - View Page

Projection `projection` - - A pop-up menu lets you choose from Perspective and Orthographic projection types. A third option Perpective to Ortho Blend enables the Projection Blend parameter below which can be used to blend between perspectives. A 4th option Custom Projection Matrix allows you to specify a custom 4x4 projection matrix using a tdu.Matrix, CHOP or a DAT.

• Perspective `perspective` -
• Orthographic `ortho` -
• Perspective to Ortho Blend `persporthoblend` -
• Custom Projection Matrix `custommatrix` -

Projection Blend `projectionblend` - Blends between perspective projection and orthographic projection when the Projection parameter is set to Perspective to Ortho Blend.

Ortho Width `orthowidth` - Only active if Orthographic is chosen from the Projection pop-up menu. This specifies the width of the orthographic projection.

Viewing Angle Method `viewanglemethod` - - This menu determines which method is used to define the camera's angle of view.

• Horizontal FOV `horzfov` - Uses the FOV Angle parameter below to set the camera's angle of view horizontally.
• Vertical FOV `vertfov` - Uses the FOV Angle parameter below to set the camera's angle of view vertically.
• Focal Length and Aperture `focalaperture` - Uses the Focal Length and Aperture parameters below to define the camera's angle of view.

FOV Angle `fov` - The field of view (FOV) angle is the angular extend of the scene imaged by the camera.

Useful Equations

Field of View and Throw Angle: The FOV would be:

FOV = arctan( (screenWidth / 2) / (distanceToScreen) ) * 2
FOV = arctan( 0.5 * (screenWidth / distanceToScreen) ) * 2

Throw is:

Throw = distanceToScreen / screenWidth
1/Throw = screenWidth / distanceToScreen

In terms of throw, it’s

FOV = arctan(0.5 * (1/Throw)) * 2
FOV = arctan(0.5 / Throw) * 2

FOV calculations in x and y

The above equations can be used to determine FOV_x and FOV_y (ie. horizontally and vertically) using Comera COMP parameters focal and aperture. In TouchDesigner's Camera COMP, screenWidth = aperture parameter and distanceToScreen = focal parameter (assuming infinity focus), from this

FOV_x = arctan( (aperture / 2) / focal) * 2

Furthermore, as mentioned above aperture parameter = aperture_x and if given the resolution in x and y of the rendered view (ie. aspect ratio)

aperture_y = resy/resx * aperture_x

From this

FOV_y = arctan( (aperture_y / 2) / focal ) * 2

Focal Length `focal` - The parameter sets the focal length of the lens, zooming in and out. Perspective is flattened or exaggerated depending on focal length. See FOV Angle parameter for relation of aperture, focal length and field of view angle. Some interesting distortion effects can be acheived with this parameter.

Aperture `aperture` - This value relates to the area through which light can pass for the camera.

Near `near` - This control allows you to designate the near clipping planes. Geometry closer from the lens than these distances will not be visible.

NOTE: If geometry in your scene is producing z-depth artifacts, increase the resolution of the camera's z-depth buffer. To do this, decrease the difference between near and far clipping planes, starting with the near plane.

Far `far` - This control allows you to designate the far clipping planes. Geometry further away from the lens than these distances will not be visible.

NOTE: If geometry in your scene is producing z-depth artifacts, increase the resolution of the camera's z-depth buffer. To do this, decrease the difference between near and far clipping planes, starting with the near plane.

Window Roll Pivot `winrollpivot` - -

• Viewport Origin `viewport` -
• Camera Origin `camera` -
• Legacy Behavior `legacy` -

Window X/Y `win` - - These parameters define the center of the window during the rendering process. The window parameter takes the view and expands it to fit the camera's field of vision. It is important to note that this action is independent of perspective. In other words, it acts as though you are panning the camera without actually moving the camera. The units for this parameter are normalized. That is a Window X of -0.5 will move the previous center of the image to the left edge of the render.

• X `winx` -
• Y `winy` -

Window Size `winsize` - The Window Size parameter specifies the dimensions for expanding the view. Similar to Window X / Y, this parameter creates a zoom effect by scaling the screen before rendering to the viewport.

Window Roll `winroll` - This parameter sets the amount, in degrees, the window area rolls. This can be set as a static value or as an aspect that changes over the course of the animation. The roll occurs about the centre of the window.

IPD Shift `ipdshift` - This is the Interpupillary Distance which applies a translation on the X axis. It is separate from the other translations because when doing things such as a Cube Map rendering, the shift needs to occur after the rotation to the other cube face. If you apply the shift directly in the X translate parameter the cameras will be in the incorrect spot for many of the cube faces.

To use the IPD with 2 cameras, the right eye camera should be set with +IPD/2 and the left eye camera to -IPD/2.

Proj Matrix/CHOP/DAT `projmatrixop` - When Custom Projection Matrix is selected, this parameters should be filled in a custom 4x4 projection matrix. For ways to specify a matrix in a parameter, refer to the Matrix Parameters article.

Custom Projection GLSL DAT `customproj` - Takes a DAT containing a GLSL shader to specify custom projection functions. You must provide one functions in this shader. As a starting point, here are the definitions for the function that is used when custom ones are not provided. This will only be used when the Render TOP is rendering a 2D output, not cubemaps or fisheye renders.

``` vec4 UserWorldToProj(vec4 worldSpaceVertPosition, int cameraIndex)
{
vec4 projP = uTDMats[cameraIndex].camProj * worldSpaceVertPosition;
return projP;
}
```

`vec3 TDWorldToProj()` will automatically call this at the appropriate point. You can use uniforms/samplers in this shader code by declaring them here and providing them in the GLSL page of the Render TOP.

Quad Reproject SOP `quadreprojsop` - Quad Reprojection is a feature that allows reprojection an arbitrary quad in the scene so that portion of the render where it ends up will be blown up to fill the output of the render. Refer to the Quad Reprojection article for more information about this feature.

Quad Reproject Points `quadreprojpts` - - Specifies 4 point indices in the SOP referenced by Quad Reproject SOP that make up the quad that determines the region to be reprojected. The indices should be listed in bottom left, bottom right, top left, top right order, as viewed from the camera. The SOP that is referenced should be in the COMP that is being rendered, so the world transform that will be applied to is can be taken into account.

• Quad Reproject Points 1 `quadreprojpts1` -
• Quad Reproject Points 2 `quadreprojpts2` -
• Quad Reproject Points 3 `quadreprojpts3` -
• Quad Reproject Points 4 `quadreprojpts4` -

## Parameters - Settings Page

Background Color `bgcolor` - - Sets the background color and alpha of the camera's view.

• Red `bgcolorr` -
• Green `bgcolorg` -
• Blue `bgcolorb` -
• Alpha `bgcolora` -

Pre-Multiply RGB by Alpha `premultrgbbyalpha` - This option allows the Background Color to be pre-multiplied by alpha.

Fog `fog` - - This menu determines the type of fog rendered in the viewport: Linear fog uses the following equation:

Exponential fog uses the following equation:

Squared Exponential fog uses the following equation:

• Off `off` -
• Linear `linear` -
• Exponential `exp` -
• Squared Exponential `exp2` -

Fog Density `fogdensity` - A value that specifies density or thickness, used in both exponential fog types. Only non-negative densities are accepted.

Fog Near `fognear` - The starting distance of the fog. If geometry is closer to the camera than this distance, fog will not be calculated in the color of the geometry. Used in the linear fog equation.

Fog Far `fogfar` - The far distance used in the linear fog equation.

Fog Color `fogcolor` - - The color of the fog.

• Red `fogcolorr` -
• Green `fogcolorg` -
• Blue `fogcolorb` -

Fog Alpha `fogalpha` - Used to control the background opacity of the scene.

Fog Map `fogmap` - Use a TOP texture as a color map for the fog.

Camera Light Mask `camlightmask` - Allows only specific lights to be used by this camera. This is used in conjunction with the Lights parameter in the Render TOP to determine what lights are used to illuminate the geometry. When this parameter is left blank, all lights specified in the Render TOP will be used. Lights specified in this parameter will limit the geometry's lighting with this camera to the light(s)specified assuming the light(s) is also listed in the Render TOP.

## Parameters - Render Page

The Display parameter page controls the component's material and rendering settings.

Material `material` - Selects a MAT to apply to the geometry inside.

Render `render` - Whether the Component's geometry is visible in the Render TOP. This parameter works in conjunction (logical AND) with the Component's Render Flag.

Draw Priority `drawpriority` - Determines the order in which the Components are drawn. Smaller values get drawn after (on top of) larger values.

Pick Priority `pickpriority` - When using a Render Pick CHOP or a Render Pick DAT, there is an option to have a 'Search Area'. If multiple objects are found within the search area, the pick priority can be used to select one object over another. A higher value will get picked over a lower value. This does not affect draw order, or objects that are drawn over each other on the same pixel. Only one will be visible for a pick per pixel.

Wireframe Color `wcolor` - - Use the R, G, and B fields to set the Component's color when displayed in wireframe shading mode.

• Red `wcolorr` -
• Green `wcolorg` -
• Blue `wcolorb` -

Light Mask `lightmask` - By default all lights used in the Render TOP will affect geometry renderer. This parameter can be used to specify a sub-set of lights to be used for this particular geometry. The lights must be listed in the Render TOP as well as this parameter to be used.

## Parameters - Extensions Page

Re-Init Extensions `reinitextensions` - Recompile all extension objects. Normally extension objects are compiled only when they are referenced and their definitions have changed.

Extension Object 1 `extension1` - A number of class instances that can be attached to the component.

Extension Name 1 `extname1` - Optional name to search by, instead of the instance class name.

Promote Extension 1 `promoteextension1` - Controls whether or not the extensions are visible directly at the component level, or must be accessed through the `.ext` member. Example: `n.Somefunction` vs `n.ext.Somefunction`

## Parameters - Common Page

The Common parameter page sets the component's node viewer and clone relationships.

Parent Shortcut `parentshortcut` - Specifies a name you can use anywhere inside the component as the path to that component. See Parent Shortcut.

Global Shortcut `opshortcut` - Specifies a name you can use anywhere at all as the path to that component. See Global OP Shortcut.

Internal OP Shortcut 1 `iopshortcut1` - Specifies a name you can use anywhere inside the component as a path to "Internal OP" below. See Internal Operators.

Internal OP `iop1` - The path to the Internal OP inside this component. See Internal Operators.

Node View `nodeview` - - Determines what is displayed in the node viewer, also known as the Node Viewer. Some options will not be available depending on the Component type (Object Component, Panel Component, Misc.)

• Default Viewer `default` - Displays the default viewer for the component type, a 3D Viewer for Object COMPS and a Control Panel Viewer for Panel COMPs.
• Operator Viewer `opviewer` - Displays the node viewer from any operator specified in the Operator Viewer parameter below.

Operator Viewer `opviewer` - Select which operator's node viewer to use when the Node View parameter above is set to Operator Viewer.

Keep in Memory `keepmemory` - Used only for Panel Components this keeps the panel in memory to it doesn't reload every time it is displayed.

Enable Cloning `enablecloning` - Control if the OP should be actively cloned.

Enable Cloning Pulse `enablecloningpulse` - Instantaneously clone the contents.

Clone Master `clone` - Path to a component used as the Master Clone.

Load on Demand `loadondemand` - Loads the component into memory only when required. Good to use for components that are not always used in the project.

External .tox `externaltox` - Path to a `.tox` file on disk which will source the component's contents upon start of a `.toe`. This allows for components to contain networks that can be updated independently. If the `.tox` file can not be found, whatever the `.toe` file was saved with will be loaded.

Reload .tox on Start `reloadtoxonstart` - When on (default), the external .tox file will be loaded when the .toe starts and the contents of the COMP will match that of the external .tox. This can be turned off to avoid loading from the referenced external .tox on startup if desired (the contents of the COMP are instead loaded from the .toe file). Useful if you wish to have a COMP reference an external .tox but not always load from it unless you specifically push the Re-Init Network parameter button.

Reload Custom Parameters `reloadcustom` - When this checkbox is enabled, the values of the component's Custom Parameters are reloaded when the .tox is reloaded.

Reload Built-In Parameters `reloadbuiltin` - When this checkbox is enabled, the values of the component's built-in parameters are reloaded when the .tox is reloaded.

Save Backup of External `savebackup` - When this checkbox is enabled, a backup copy of the component specified by the External `.tox` parameter is saved in the `.toe` file. This backup copy will be used if the External `.tox` can not be found. This may happen if the `.tox` was renamed, deleted, or the `.toe` file is running on another computer that is missing component media.

Sub-Component to Load `subcompname` - When loading from an External `.tox` file, this option allows you to reach into the `.tox` and pull out a COMP and make that the top-level COMP, ignoring everything else in the file (except for the contents of that COMP). For example if a `.tox` file named `project1.tox` contains `project1/geo1`, putting `geo1` as the Sub-Component to Load, will result in `geo1` being loaded in place of the current COMP. If this parameter is blank, it just loads the `.tox` file normally using the top level COMP in the file.

Re-Init Network `reinitnet` - This button will re-load from the external `.tox` file (if present), followed by re-initializing itself from its master, if it's a clone.

## Info CHOP Channels

Extra Information for the Camera COMP can be accessed via an Info CHOP.

### Common COMP Info Channels

• num_children - Number of children in this component.

### Common Operator Info Channels

• total_cooks - Number of times the operator has cooked since the process started.
• cook_time - Duration of the last cook in milliseconds.
• cook_frame - Frame number when this operator was last cooked relative to the component timeline.
• cook_abs_frame - Frame number when this operator was last cooked relative to the absolute time.
• cook_start_time - Time in milliseconds at which the operator started cooking in the frame it was cooked.
• cook_end_time - Time in milliseconds at which the operator finished cooking in the frame it was cooked.
• cooked_this_frame - 1 if operator was cooked this frame.
• warnings - Number of warnings in this operator if any.
• errors - Number of errors in this operator if any.

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