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SketchUp Camera

For each Scene in your SketchUp model, the plugin will create and maintain an associated Maxwell camera.

Toolbar

The Camera panel's toolbar contains the following items:

ItemDescription
Undo/RedoThese two drop-down lists hold the history of actions which have been executed in the camera panel. They are cleared when a new document is opened, or when a different camera is selected.
ViewThis button toggles the Camera panel between its Minimal and Advanced views. When the Minimal view is active, only the most often used camera parameters are shown.
Presets ListThis drop-down provides a list of camera presets which have been stored previously. To remove a particular preset, click the red X next to its name in the list.
Add PresetClick this button to store the current settings as a new camera preset.

Output Resolution

This section determines the output dimensions of the rendered image. It operates in two basic modes: Viewport and Custom.

In Viewport mode, the plugin will match the camera's output resolution to the size of the associated SketchUp viewport. In Custom mode, the camera's output resolution may be defined independently of the physical size of the viewport. A list of common resolution sizes is provided in the Preset drop-down. Additionally, there are two other parameters which come into play in Custom mode.

Lock Aspect Ratio

When enabled, aspect ratio of the output resolution will be maintained during adjustment of either its values.

Show Aspect Ratio in Viewport

When using Custom mode, it is likely that the aspect ratio of the Maxwell output will not match that of the SketchUp viewport. In order that you might be able to accurately predict the composition of your image, the plugin provides the Show Aspect Ratio in Viewport feature. When this is enabled, grey bars will appear in the SketchUp viewport, framing the area which will appear in the render.

Notes on Output Resolution in the Standalone Plugin

The Standalone plugin renders images using Maxwell Fire. If the output resolution specified in the camera is larger than Maxwell Fire's Max. Resolution, it will be adjusted, with its aspect ratio being maintained. The Free license allows a Max. Resolution of 800 pixels, and the Commercial license, 1920 pixels.

Focus & Exposure

A camera's exposure is the result of the combination of its fStop, Shutter, and ISO values. As the fStop value is decreased, more light enters the camera, brightening the exposure. Conversely, as the Shutter value is increased, the film is exposed for a shorter duration, darkening the exposure. As the ISO value of the film is increased, its sensitivity to light increases, allowing a given exposure to be achieved in a shorter amount of time. The camera may be focused manually, or automatically by the plugin, using one of three different strategies.

Focus

By default, camera focus is defined manually, using the Set Focal Distance tool. Optionally though, you may elect to have the plugin auto-focus the camera for you. There are three auto-focus sampling modes available:

ModeFunction
SpotThis mode samples focal distance using a single ray located at the center of the viewing plane.
AverageThis mode samples focal distance using a circular set of rays, the diameter of which is roughly half the size of the viewing plane, and arranged around its center.
Average + DOFThis mode is identical to Average mode, but also takes control over the camera's fStop, automatically setting the camera's near and far focal distances.

As such, Spot sampling mode will focus based on the distance of the object it finds located directly in front of the camera. Average mode will focus based on the average distance of objects it finds near the image's center. Average + DOF mode performs an Average sampling, and uses the nearest and furthest distances to set the camera's fStop; as a result, direct fStop adjustment is disabled when using this mode.

In extreme cases, the Average + DOF mode may have difficulty finding the desired focus range; when this happens, it will usually be best to revert the use of Manual or Spot mode.

Exposure

The fStop, Shutter, and ISO values may combined together mathematically to express an EV (Exposure Value) number, which describes the overall exposure of the camera in terms of a single number. Lower EV values are generally suitable for lower-light scenarios, and vice versa. Where a candle-lit scene may require an EV of 4-6, a bright sunlit scene may require something more on the order of 13-16. A chart of EVs for various scenarios can be found at the end of this manual.

Additionally, where Shutter and ISO primarily affect the brightness of the exposure, the camera's fStop also affects its DOF (that is, Depth Of Field: the distance between the nearest and farthest distances which will be in focus in the image). This often becomes an issue, because it is many times desirable to adjust the fStop for purposes of achieving a desired DOF in the composition; however, when this is done, the exposure is also affected, due to the change in fStop, even though this is not part of the desired effect.

To address this, the camera provides the Lock Exposure to EV feature. When activated, it is not possible to directly alter Shutter and ISO; these values will be managed by the plugin as either fStop or EV are changed, maintaining a consistent final exposure. This makes it possible to adjust the camera's DOF without also affecting the exposure, or to adjust the exposure directly by adjusting EV, without being concerned with the somewhat complex relationship between fStop, Shutter, and ISO.

For a more comprehensive introduction to the Maxwell camera, please see the Camera page in the Maxwell documentation.

Advanced View

When the Camera panel's Advanced View is enabled, several additional parameter groups are shown.

Diaphragm

Diaphragm refers to the type of aperture used by the camera; there are two types: Circular and Polygonal. When a Polygonal is used, the shape of so-called Bokeh effects will be determined by the number and Angle of the Diaphragm's Blades. Please see the Camera page in the Maxwell documentation for more details.

Z-Clip Planes

If you wish, you can choose to clip geometry at render-time, using a near and far plane, which are both set perpendicular to the camera's direction. The Near distance specifies how far from the camera the near plane is located; any geometry between this plane and the camera will be clipped from view. Similarly, any geometry farther away from the camera than the Far plane will also be clipped from view. Please see the Z-clip planes page in the Maxwell documentation for more details.

The Z-Clip Planes may be set interactively using the Set DOF, Z-Clip, or Z-Buffer Tool; to do so, press SHIFT while selecting points with the tool.

Shift Lens

It is possible to shift the camera's film along its X and Y axes, with respect to the lens. This is often useful when rendering tall buildings; the camera can be set such that its direction is parallel with the ground, with its height being a meter or two above the ground. The film may then be shifted downward, moving the building more into the center of the view, while avoiding the perspective distortion which would result from angling the camera upward to achieve a similar composition. Please see the Shift Lens page in the Maxwell documentation for more details.

Although this is similar to using SketchUp's two-point perspective, the effect of the shift lens cannot be visualized in the SketchUp viewport, due to SketchUp API limitations. It can, however be visualized using Maxwell Fire.

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