Align View

When using a scanned photograph as the background of your rendering, you may want to fit your ArchiCAD model into the photograph’s environment. In the photorendering made from the Camera placed by the Document > Creative Imaging > Align View command, the perspective of your building in ArchiCAD will match the perspective of the background.

For more information, see PhotoRendering.

For this feature, you need to select two clearly visible vertical segments on the photograph (e.g., the sides of a door or a window, two vertical edges of a wall, or two flagpoles), and connect them with their exact position in the virtual model or its environment. This is done by connecting each of four points on the placed photograph (the tops and bottoms of the two vertical segments) with their position on the Floor Plan, and then entering their Z coordinates in the Align View dialog box.

Note: This function is mainly useful in refurbishing, when a photograph of the existing environment is available.

Align View: Interior Example

Using the Figure tool, place the scanned image on the Floor Plan at any size or resolution.

For more information, see Figures.

You then have two possibilities for aligning the camera view to the photograph: you can either use existing lines or can manually draw lines between the corresponding points of the Floor Plan and the photograph.

To draw the connection lines automatically:

1.Select the placed photo.

2.Choose the Document > Creative Imaging > Align View command. ArchiCAD will prompt you to make six clicks on the Floor Plan with the Pencil cursor, identifying the corresponding points between the picture and the plan. The connection lines are drawn automatically.

The Align View dialog box appears, prompting you to enter the height values for the four points.

3.Click OK. The camera will be placed on the Floor Plan on a new path.

To draw the connection lines manually:

1.Using the Line tool, connect the tops and bottoms of two vertical lines visible on the photograph with their location on the Floor Plan (e.g., the sides of a door or a window, two vertical edges of a wall, or two flagpoles). This will give you four lines, each extending from a floor plan location to a point on the photograph, with the two line pairs connecting where they meet on the Floor Plan.

2.Select the photo and the four lines.

3.Choose the Align View command. The dialog box appears, prompting you to enter the height values for the four points.

AlignViewDlg.PNG 

4.Click OK to close the Align View dialog box. The camera will be placed on the Floor Plan, on a new Path.

PhotoPlan.PNG 

Select the elements you wish to display on the image, then select the Camera, and choose the Document > Creative Imaging > PhotoRender Projection. In the picture below, only the Object type elements have been selected on the Floor Plan and they appear against the backdrop of the scanned photograph.

PhotoMix.PNG 

Note: For greater precision, you can enter the horizon of the photograph by simply rotating the picture on the Floor Plan so that the horizon is exactly parallel to the unskewed x-axis (otherwise the command will calculate the horizon for you). The precision of the result depends largely on that of the entered points, but even very careful preparation may result in a Camera that is slightly off position. In this case, set the photograph as the background of your 3D window, and fine-tune the Camera’s position in Wireframe or Hidden Line mode using ArchiCAD’s 3D navigation tools.

Align View: Exterior Example

Let’s say you have a photograph of a building and its plan as an ArchiCAD file. Place the original photo on the Floor Plan of the building. If the picture is placed without any rotation then the horizon is calculated automatically as horizontal. You can, of course, override this horizon calculation manually, and enter the horizon angle yourself; this is done by rotating the picture on the floor plan. When the picture is rotated with an angle other than 90º (or 180º or 270º) on the floor plan, then Align View calculates the horizon by itself, otherwise the horizon is assumed to be horizontal. You need to know the height values of two vertical lines (four points in all) on the building and their locations on the photo.

AlignViewNL1.PNG 

Two black hotspots on the Floor Plan and the heights of two distinct points of the building below each are shown on the illustration. Zoom in on the photo and place four hotspots at the locations of the four points with known height values.

Select the photo and choose Document > Creative Imaging > Align View.

To link the hotspots, click first on the point on the Floor Plan that corresponds to hotspots on the photo. (In the above example, the side of the window on the left where you see the black hotspot with two heights, +2.64 and -2.21.) Now click the pair of hotspots on the photo, one after the other. Repeat this operation with the other point on the plan and the corresponding pair of hotspots. It does not matter which point on the Floor Plan you start with. In addition, after marking a point on the Floor Plan, you can select the two corresponding points on the photo in either order.

AlignViewNL2.PNG 

When correctly done, the result will look as shown above, and the Align View dialog will appear.

Type the height of the hotspots in the appropriate fields in the dialog box. The upper points are located along the same vertical line as the lower points. In this example, these will be 2.64 and -2.21 meters (left upper and lower) and 3.08 and -3.40 meters (right upper and lower). After you click OK, a new camera will be placed on the Floor Plan.

Select the original scanned photo to be the background picture in the PhotoRendering Settings dialog box. Make sure the width-height ratio of the resulting PhotoRendering is the same as that of the original photo. You can also modify the size of the photo to suit the size of your PhotoRendering window.

Note: You cannot crop the photo. If you must, crop it in a way that the original proportions of the photo stay the same (i.e. cover a part of the photo with a solid white fill), because Align View needs the original proportions of the picture to locate the original target point of the photo. The view will not be aligned precisely if the proportions of the photo have been changed.

For example, if you have a scanned picture of 1200 x 900 and you want a 3D window or PhotoRendering window image of 600 x 450, you would reduce the size of the background photo to 50 percent in the PhotoRendering Settings dialog box. (You can choose this same background in the View > 3D View Options > 3D Window Settings dialog box: click the “Background: As in PhotoRendering” radio button.) By selecting the created camera and generating a 3D View or a photorendering, you will see the result - the building is accurately placed in the existing environment.