Matching a Photo to a Model (or a Model to a Photo)

SketchUp’s Match Photo feature has inspired many happy dances, because it enables you to

• Apply a photo to an existing model: Say you have a model of an existing structure and you want the model to look realistic. Applying a photo with Match Photo is much easier than drawing that detail and applying materials to individual elements.
• Create a model from a photo: When you want to model an existing structure, Match Photo enables you to use a photo as a starting point. You can essentially trace the photo to draw the model.

Until you get the hang of Match Photo, you may suspect that SketchUp dumped a box of rainbow spaghetti on your model like a toddler bored with pasta crafts. Match Photo is a bit confusing at first, but this article gives you the tips and steps that you need to use Match Photo in the magical way its developers intended. When you’re first learning how to use Match Photo, orient yourself to the color-coded tools that Match Photo spills onto your screen and check out what photos work well with the Match Photo feature. Then try your hand at matching a photo, following the detailed steps in the following sections.

Introducing Match Photo’s color-coded tools

To start using Match Photo, select Camera > Match New Photo. Select the photo you want to use, and your screen looks something like the following figure, which shows an image captured from Google Street View. The following list identifies all the tools that appear on-screen:

1. Scene tab: A scene is a saved camera view of your model that’s associated with a tab. If you orbit away from this particular view, the matched photo disappears. But you can click the Match Photo scene tab to return to the view with the photo.
2. Match Photo view: When the camera is in Match Photo view, you see Match Photo in the upper left of the drawing window.
3. Vanishing point bar: You see two green bars and two red bars with dashed lines and a square grip on each end. You click and drag the grips to align these bars with elements in your photo.
4. Horizon line: This yellow line aligns with the horizon in your model. Typically, if you set the vanishing point bars, the horizon line takes care of itself.
5. Axis bars: The solid green, red, and blue lines represent each axis. As you adjust the vanishing point bars, the axis bars move, too, so you usually don’t need to adjust these manually. You can click and drag up and down the blue axis bar to roughly scale your photo.
6. Axis origin: The origin is where the three axes meet. If you start with a Match Photo-compatible image, Match Photo does a pretty good job of locating the origin for you, but you might need to adjust it a bit. In the example, the origin needs to move down a bit so the axis origin is at the corner where the walls and ground meet. (If the photo looks down on a building, try a corner where the roof and walls instead.) For a photo taken indoors, place the origin where the walls and ceiling or the walls and floor meet in a corner.

Choosing photos that work with Match Photo

Match Photo works best when your photo meets certain criteria. When you’re taking or choosing photos to use with SketchUp’s Match Photo feature, keep the following tips in mind:

• Match Photo works best with structures made mostly of right angles. You definitely need at least one right angle for Match Photo to work.
• Use photos taken at a roughly a 45-degree angle from a corner. The preceding figure from Google Street View is an example of an image taken at a 45-degree angle. If you’re taking photos, you can use Match Photo on several parts of your model if you take photos of each corner.
• Do not crop photos. Although it may seem possible to use a cropped image, typically vertical lines don’t align well across a cropped image, and you won’t like the result.
• Avoid warped or distorted photos if you can. Match Photo doesn’t work best with images that an image editor or specialized camera has warped. For example, because the Google Street View camera warped the image of the preceding building a bit as the camera went around the corner, the vanishing point bars, axes, and horizon may not line up precisely. However, the school house photos used later in this article match up exactly with the model, because the photos had no distortion at all.
  
  Tip: Sometimes an image editor can remove barrel distortion or issues where straight lines are bent away from the center of the image. Barrel distortion typically occurs on wide angle lens cameras.


• Avoid stitched images (panoramas). Stitched images are typically excessively warped and have multiple vanishing points for each axis.
• Choose photos without foreground features. When trees and other foreground objects block the view of a building, those foreground elements get in the way of drawing a model based on your photo.
• Make sure your image has two vanishing points. You’ll have a hard time adjusting the vanishing point bars if your image has only one, infinite vanishing point, such as a hallway or a long train track. Similarly, images taken with a very long telephoto lens (or a satellite or aerial image) also make adjusting the vanishing point bars difficult.

Matching a photo with an existing model

To apply a photo to an existing model with SketchUp’s Match Photo feature, have your model and your photo on your hard drive. When you’re ready, follow these steps:

1. Select File > Open and select the model you want to open in the drawing area. This example uses the following model of a schoolhouse.
   

   

2. Select Camera > Match New Photo.
3. In the Select Background Image File dialog box that appears, navigate to your image file and click Open. The camera switches to Match Photo view, so your photo appears in the drawing area, as shown in the following figure, and your camera angle is automatically saved to a scene tab, which appears in the upper left.
   

   

   Tip: When a Match Photo is active, you can context-click any Match Photo tool to open a context menu. Select Start Over or Cancel Match if your photo matching goes awry. Select Zoom Matched Photo to fit your photo in the drawing area. Zoom Vanishing Points zooms so that all the vanishing points fit in the drawing area.
4. In the Match Photo dialog box, shown in the following figure, select the style that reflects the type of photo you have. Click Inside for an interior image, click Above for an exterior photo of a building taken from the top, or click Outside an exterior photo taken from the ground.
   

   

   Tip: You can adjust the grid to suit your preferences and help you align and scale your photo. Select the Auto radio button to make the grid appear only when you’re adjusting one of the matching tools. (The vanishing point bars, horizon bar, and axes are always visible in Match Photo view.) Use the Planes options to select whether you want the grid to show the red/green, red/blue, or green/blue planes. Type a value in the Spacing text box to set the size of the grid spacing, which can help you scale your model to a multiple of the actual structure’s size.
5. Click and drag the axis origin to a distinct origin point on your photo. In this example, that’s the corner where the building meets the ground, as shown in the following figure. See Introducing Match Photo’s color-coded tools for tips on setting the axis origin.
   

   

6. (Optional) Clear the Model checkbox to hide your model from view. You don’t have to hide your model, but it’s often a little easier to line up the vanishing point bars with the photo if the lines in your model aren’t competing with your photo.
7. Click and drag the grips on each of the four vanishing point bars. Align the green vanishing point bars with photo elements that need to be parallel the green axis bar. Make the red vanishing bars align with photo elements that are parallel with the red axis bar. The example in the following figure illustrates how the vanishing point bars align with their respective axis bar.
   
   Tip: Window frames, door frames, and roof lines are handy reference points for aligning the vanishing point bars. Also, the longer the vanishing point bar extends, the better your results.
   
   

   

8. Select the Model checkbox in the Match Photo dialog box so that your model reappears.
9. Hover the cursor over the blue axis bar. When a two-headed arrow cursor appears, click and drag the cursor up or down the blue axis bar to scale your model. You want the model outline to line up with your photo, as shown in the following figure.
   

   

10. (Optional) In the Match Photo dialog box, click the Project Textures from Photo button to project the photo on the model. If you project textures, you can see the photo applied to your model’s faces as you orbit around you model. The following figure shows textures projected on the schoolhouse example.
    
    Note: If your model already contains materials, SketchUp asks whether you want to replace the existing materials. You may also see the Trim partially visible faces? message. If so, click Yes to apply photo textures only to the visible portion of faces in your model. Click No to apply textures to an entire face, even only a part of the face is visible.
    
    

    

11. Click the Done button to exit the Match Photo toolset.

Creating a 3D model from a photo

If you have a photo of something you want to model, Match Photo can help you draw the 3D model.

To draw a model with the help of a photo and SketchUp’s Match Photo feature, follow these steps:

1. Follow the steps in the preceding section, “Matching a photo with an existing model,” to set up your axis origin, vanishing point bars, and scale. The only difference is that you don’t need to worry about opening the model that goes with your photo or projecting textures onto a not-yet-existing model. These steps explain how to draw the model based on your photo.
   
   Tip: To help you set the scale of your photo, insert one of SketchUp’s 2D people, as shown in the figure. If you don’t already see one of these folks in your model already, find them in the Components panel.
   
   

   

2. Select the Line tool ().
3. Starting at the axis origin, trace one of the edges in your photo. Continue tracing edges until you create a face.
4. Use SketchUp’s tools to continue creating your 3D model based on the photo. For example, after tracing the side of the barn shown in the following figure, you might use the Push/Pull tool () to extrude the face, as shown in the following figure. When you use the drawing tools, you’ll likely leave the Match Photo view. Click the Match Photo tab see your photo again and check the length of your extrusion against the length of the barn in your photo.
   

   

   Tip: The process of modeling from a photo is iterative. You’ll likely do a little drawing, check your model against the photo, do a little more drawing, and so on.
5. (Optional) Click the scene tab to see your photo and project the photo textures onto your model. To do so, click Project Textures from Photo in the Match Photo dialog box or context-click the photo and choose Project Photo from the menu that appears. In the figure, you see the barn textures projected onto the model.
   

   

Deleting a matched photo

If your matched photo didn’t work out or you don’t need it any more, you simply delete the Match Photo scene. Here are two ways to do so:

• Context-click the scene tab and select Delete from the menu that appears.
• Open the Scenes dialog. In the Scenes dialog that appears, select the scene with your matched photo and then click Remove Scene (the minus sign icon).