The Align View Function in Graphisoft’s ArchiCAD, allows you the architect to offer value to your clients.
When designing an addition or renovation to an existing building, it is valuable to see and show the new design elements in context. Clear depiction of how the new work impacts the existing building and surroundings works to relieve the anxieties of owners and neighbors, and is required in some cases by design review boards. With ArchiCAD’s Align View command, setting a photo as the background of a 3D model is a snap!
For the purpose of this post, we have chosen a project in which we designed a second-story/room addition to a 50’s era ranch style home in Seattle, WA. The goal was to expand the living area and capture a view of Puget Sound from the upper floor. The addition was also designed to take advantage of the sun and site. Being able to see the new design on the existing site before it was built helped to shape the design.
To accomplish this we needed a photo of the existing house, and a model of the addition. We use Graphisoft’s ArchiCAD for all our modeling and rendering and to prepare the 2D documents necessary for permits and contractors. In this case we did not need to model the existing house, since it was not being altered. However we were able to bring in the existing plans and elevations from DWG files of a previous remodel for reference.
The Align View command works by automatically placing a Camera and calculating its position, matching the perspective of a photo.To do this accurately you will need to know the heights of two elements in the photograph and where those points are in plan. In our case, we knew the height of the exterior wall. (TIP: the longer the dimension is the more accurate result you will get.)
First we placed the photo on the Floor Plan using ArchiCAD’s Figure tool.You can keep the Figure Size and Resolution, as well as the other settings at their default values. Simply place the photo by clicking on the plan view. (TIP: it’s a good idea to place it nearby the model.)
With the photo placed, add two sets of Hotspots at the known points of the building. (This will make it easier on you later on.) Now select the photo and star t the Align View command from the Document > Creative Imaging menu.
With the Pencil cursor, draw four lines.These will “connect” the points on your model to the points in the photo. Click the point on the model first, then click the bottom and the top of the corresponding points on the photo. After you have one set done, you will see two new red-dashed lines. Now complete the next set of points.
Once the points have been set, the Align View dialog will appear. Enter the heights of the four points.You will want to enter the values relative to Project Zero. In our case, Project Zero is at the First Floor level.
When done correctly, you should see a new Camera on the plan located where you took the photo from. If not, check the previous steps and try again. We have found the Align View command to be very accurate as long as you input correct values.
You will also see the new Camera in the Navigator – Project Map under Align View Path. If the Camera position looks correct, double-click the Camera in the Project Map to open the 3D window.You won’t necessarily see the photo in the background yet, but the perspective should look like it will match.At this point you should also make sure the correct Layers are showing.
Set the 3D Window size and ratio to match the photo.This is controlled in the 3D Window Settings found in the View > 3D View Mode menu. Hang in there, because now we are ready to go back to the Document > Creative Imaging menu and adjust the PhotoRendering Settings.
Set the Engine to LightWorks Rendering Engine, and click the Size to 3D Window button. (Note for Start users, since LightWorks is not available you should use the Internal Engine.) We will leave the Effects set to the default Factory Settings, and click the Render Background with Internal Engine checkbox under LightWorks Environment.This allows the Background settings we will adjust next to take effect.
Choose the Picture radio button and click Change Picture.This opens up the Load Image from Library dialog where you can select any photo loaded with the Library.You can also load a photo directly which is what we can do here by clicking Load Other Object from File Dialog Box.
Select the same photo that was placed earlier on the plan. Now it will also show up in the background of the PhotoRendering window.The preview should show the entire photo filling the window. If not, try adjusting the Resolution.
If everything looks correct, you are ready to render! Hit OK and go back to the Document > Creative Imaging menu one last time, this time selecting PhotoRender Projection…
There you have it. Our model is perfectly aligned. For best results, remember these TIPS:
- Make a high resolution photo of the building site with sharp contours and good lighting.
- Avoid 3 point perspectives, lens distortions, fisheye view, etc., as much as you can.
- Remember the position of the sun when the picture was taken.
- Take the plan to the building site with you and check if the distances are correct. Mark the location of the points which you would like to use for camera positioning.
- Measure the height of those points on the building site, which you will use for the Align View camera definition.The bigger distances between the points, the better.
- When you define the camera positioning points in ArchiCAD make sure to place them precisely.
- In the photo rendering settings, set the same size for the rendering window as the size of the original photo.
- Position the sun according to the conditions when the picture was taken.
The Align View command is a handy utility for visualizing your project in the existing environment. In our next article we will show you how to place your model into Google Earth.