You're going to use the tool Match Photo to set up the SketchUp camera, so that it matches the position and focal distance of the camera you used to take your photo. Before SketchUp Version 6, we used to do this by trial and error, but since Version 6, SketchUp includes Match Photo, which automates the whole task for you. Using this feature, you can create "before" and "after" photos that are very useful for renovation projects, such as the home extension shown in the following image. The realism that the architect has achieved here wouldn't have been possible without exactly matching the camera view:

First, some points about the kind of photographs you need to take:

For a before and after scene, it is important to make a note of the following important details:

These allow SketchUp to recreate the position of the camera and sun. You might wish to use the sky's photo to select similar sky settings in your rendering application or to pick a similar HDR sky for rendering (for example, clear, cloudy, or overcast).

Match Photo works by recognizing perspective foreshortening in the frame. In order to do this, there have to be some buildings or walls or other items with right angles. All you have to do, is open the photo in SketchUp and line up some colored lines with these features.

SketchUp has now created a new scene (see the tab at the top of the 3D window), which you can click on whenever you want to come back to this view. You will see the image only in this scene. If you move the viewpoint away from the viewpoint of the image, the backdrop will disappear.

You have now set up the blue, green, and red axes to correspond to the up/down, forward/backward and left/right directions that you have captured in the photograph. Having done this, you can now happily draw away in the scene, knowing that the model you create will always look as if it is right within the photograph. The depth of the field, focal length, and eye height have all been taken care of. This is a big deal, because doing this by trial and error would have taken far more time and probably caused a lot of frustration!

You can now test your new perspective setup by drawing a simple box into the scene. If this looks right in relation to the photo, you know you've done the Match Photo process correctly.

The perspective of this box should be in keeping with the house, wall, or any other right-angled item that you included in your photo. If it isn't, just click on the photo match pallet, click on the cogs symbol to edit the Match Photo setup, and tweak the dotted lines. The best indication that you're right is when the blue axis lines up perfectly with the corner.

You have just created a 3D box to represent the existing building. Rotate the view with the mouse to view it. Notice that the photo disappears. Don't worry; you can bring it back at any time by clicking on the scene tab that the Match Photo tool created at the start.

You can now draw or add anything onto this scene, and it will look correct if you place items into the scene in relation to the 3D box, as you can see in the following screenshot:

All that remains is to tell SketchUp what time of day and date the photo was taken. You can do this with the Shadow Settings dialog box, as shown in the following screenshot:

You have now set the location, orientation, time, and date of your site. This means that the Sun and shadows will behave just as they would if you were really there.

Check the shadow cast by the box. Does it match with the photo? If not, you may have got the North orientation mixed up or forgotten to set the correct location. You can go back and change this now. You can also use trial and error on the sliders for the date and time to match the shadows in the photo as closely as possible.

Now that you've learned everything you need to know about setting up a physically accurate environment, let's look at the other great methods you can use to set up a site in SketchUp. Don't forget; even though shadows and shading look quite cartoony now, these settings will be used to define the physically accurate Sun and sky conditions when you export them to a renderer.

Follow these basic steps to clean up your CAD drawing for use in SketchUp:

You now have a basic plan from which you can begin modeling the environment around your building and the building itself. Now, you need to import it into SketchUp at the correct scale.

In the following screenshot, you can see an imported CAD plan scaled to the right size. You can compare the size of the person with the size of the door opening or a chair to confirm the correct scale.

You now have the plan within SketchUp and scaled to real-world dimensions. This is important, because SketchUp is built for real-world architectural models, and every component you will add to your model (such as persons or plants) will come in at a realistic size.

If you only have a few layers in your CAD file, you can leave it at that. However, if there are dozens of layers in the file, these have now been replicated in SketchUp. It's time to do a bit of cleanup work:

CAD applications use layers to separate elements. In SketchUp, all the basic elements should be drawn on Layer0, and only the containers (groups and components) should be assigned to a different layer to control the visibility of the object. We have created this structure in SketchUp and at the same time, got rid of a number of imported layers that are not useful to us.

If you are lucky and can get a ready-made 3D model for your visualization project, you can also import the entire 3D model into SketchUp. The supported formats are as follows:

When you import 3D content from another application, you have to be careful with the complexity and level of detail. CAD and BIM models can be large in dimensions but still model every detail down to the doorknob in very high resolution. If you actually succeed with the import, the performance of SketchUp will certainly suffer.

Most CAD applications will create triangle surfaces when exporting 3D objects, because these are the most basic objects that every application can handle. In SketchUp, we would prefer to have complex polygonal faces to make use of the native surface tools. Luckily, there is a plugin that can combine triangles to polygons for us. It is Cleanup by Thomthom. You can download it from the Plugin Store.

Although importing a finished 3D model may look like a big time saver, you will find that you will have to spend a lot of effort on cleaning up, restructuring, and converting the triangular surfaces into something that can be easily handled and modified with SketchUp. Therefore, directly importing CAD or 3D data is most useful for objects that you are not going to edit a lot, such as a car or a surrounding urban block. If you are going to make a lot of modifications to the geometry, it may be faster to recreate the model from scratch with all the tools and the correct structure of a SketchUp model.