You can import one or more image files and place them on the ground plane of your CityCAD model.
For example, you could import aerial photos or scale plans and then trace over them with CityCAD routes.
To start, click the Ground Plane Images button on the CityCAD Toolbar, or by selecting File Menu: Import: Ground Plane Image.
There are three buttons for inserting images.
- Add in 3D View - allows you to browse for an image file, and then place it in the Main Display Window by drawing a box from bottom-left to top-right.
- Add using 3 reference points - allows you to browse for an image file, then place by 3-point positioning)
- Add at same position (Only available once an image has already been imported) - allows you to import an image and for it to be automatically placed at the same location as an image that you imported earlier.
Remove Image - the red delete button allows you to delete an image which you have already imported.
Move Up/Down - the green up and down arrows enable you to move the images up and down in the grid, changing the display order. All images are displayed at the same level as the ground plane, but images higher up in the list will appear on top of images further down the list.
Refresh from image file (Only available once an image has already been imported) - allows you to select an image in your model and update it with another image file. Please note this will replace and delete the previous image from your CityCAD file.
There are five columns which can be displayed in this grid:
- Name - the filename of the imported image files.
- Index - a unique reference number for the image.
- Details - the size of the image in pixels, and the approximate size in the model.
- Display - you can switch the visibility of individual images on/off by checking this box.
- Transparency - You can adjust the transparency of each image file using this sliding control.
(You right click on the grid header to display the column chooser to add or remove columns, but we recommend these are unchanged. You can also display the unique ID for each image. This ID is only used for CityCAD's own internal reference.)
The bottom half of the window is divided in to two preview boxes.
- The bottom-left box displays a 2D plan of your current city model (including any imported images).
- The bottom-right box displays a preview of the currently selected image file (selected in the list above.)
In the bottom-left corner of the window, there are four tools for navigating around in the preview boxes. From left to right:
- Reset View - restores view to default.
- Zoom In - you can use this tool to draw a rectangle in the preview box to zoom in to a specific area.
- Zoom Out - you can click in the preview box with this tool to zoom out.
- Grab Tool - this tool works the same way as the grab tool in the main display window, and can be used to pan around the 2d plan or the image preview.
3-point positioning controls
At the bottom of the window, next to the four tools, are three buttons marked '1', '2' and '3'.
These are used to create reference points. Press the button '1', and you can then click in either preview box to set reference point 1. (You can click repeatedly several times, and it will update the reference point each time.)
You can repeat this for '2' and '3' to create the second and third reference points. Once the third reference point has been set in both boxes, then the selected image will appear in the 2d plan preview on the left.
The status outputs ("Set" or "Not Set") display which reference points have been set and which still need to be done.
Assistance with Positioning
There are two controls which can help you position image more accurately - 'Distance between 1 and 2' and 'Auto Set Point 3'.
If you have already set points 1 and 2 in the left hand preview box, then the distance between the two will be displayed. You can use this for reference, or if you know that point 2 should be a specific distance away, then you can type this in and click 'Set'. Point 2 will be moved so that it is that specific distance away from point 1.
Also, if you have already set points 1 and 2 in both preview boxes, then you can click 'Auto Set Point 3', which will place point 3 at 90 degrees to the line 1-2, and at the same distance away from point 1 as point 2 (See diagram below).
The Ground Plane Images window can be re-sized. Also, the vertical divider between the two preview boxes, and the horizontal divider below the image list are both adjustable.
Hints and tips for importing images
Important - images imported using this window can be distorted, and should only be used for broad feasibility testing. If more accuracy is required, we recommend you import a DXF ground plane base map.
- Importing a sketch or aerial photo is easier if you add a scale grid (eg. 100m grid) to the image file before importing it.
- If you are importing an image of a map without a grid, but with a scale bar, then draw points 1 and 2 anywhere on the left hand preview box anywhere but in a horizontal line (1 on the left, 2 on the right), then in the right hand pane place points 1 and 2 at either end of the scale bar. Then enter the distance of the scale bar and click 'Set', then click 'Auto Set Point 3'.
- When using 3-point positioning, you can zoom in by using the mouse wheel button which can help you place the locator points more accurately. When you zoom in to the 2d plan on the left, the urban design grid will adjust - ie. if you zoom in further the 10m and then the 1m grid will appear, allowing you to place images more accurately.
- By default, the Ground Plane Window is quite small - you may find it easier to expand the size of the Ground Plane Image window when positioning images. You can drag the edges of the window to grow or shrink the window.