SketchUp Background

In order to give a Sketchup model a more photo-realistic look or to set it within a particular environment we may want to add a background image. This may be either a random landscape image or a particular view for the purposes of 3D planning within a specific site. In this way it's possible to add image files to our model and adjust their positions so that the model blends seamlessly with its site surroundings. Alternatively we could place an image behind a building so that it's possible to study the sight lines from certain angles within the building.

To add an image to a SketchUp model we first open the Window drop-down menu and choose Styles. We then click on the OK icon which opens a dialog box labeled Watermark Settings. Next click on the Plus icon to browse to where your image is stored, then select Open.

We now select either Background or Overlay, the former being more common. This option will add the image as a backdrop to our scene, whereas the Overlay option will place the image on top of the view of the model. We may also wish to change the transparency of the image or to choose whether to stretch or tile the image. And of course we may need to first adjust the tones and colours in a photo-editing program like Adobe Photoshop.

In this case we would open up the image within Photoshop and go to the Image drop-down menu on the top of the interface, and choose Adjustments and Levels. This will open a dialog box showing a Histogram which represents the pixel values of the image as points on a graph. Each pixel in the image has a number for colour and brightness, so that whenever we wish to make changes to the an image we often have to select a group of pixels. In this case we want to adjust the overall tonality of the image. Ignore the Output Levels - this is for print professionals to adjust ink levels. Go to the Input Levels section and move the black stop on the far left inwards by a few millimeters - this will add more black to the image. Repeat this for the white stop on the right hand side - this will introduce more white in the image. And finally adjust the grey mid-tone stop - this will rebalance the tones within the new values for pure black and pure white. Untick Preview to see the result, and if you
are happy click OK and res ave the image. A similar colour adjustment can be made within the Hue/Saturation adjustments.

Note that SketchUp allows you to import various file formats as background images: JPEG, PNG, PSD, BMP and TIFF images are all valid.

One drawback of the process is that the image will remain static throughout an animation, so if the camera is moving through the scene, as in a fly-through or walk-through animation, the parallax of the background will not move in a realistic fashion, destroying the realistic setting effect. If the camera is simply zooming and panning in the scene such a setup will work, however. Any orbiting of the camera will not. In such a case it may be better to project the image onto a wide cylindrical object placed around the whole scene.

A related concept is how to import a graphic image as a reference to assist in the actual creation of the model. This technique is called Photo Matching. And another related concept is importing your own textures to be applied to either flat or curved surfaces.


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Tom Gillan has been training sketchup courses to corporate clients in Sydney for seven years. If you like to know more about sketchup, visit http://www.designworkshopsydney.com.au/sketchup-courses/ for more information.