3D FeatureXtract Simple Building Extraction

Transcription

1 3D FeatureXtract Simple Building Extraction 3D FeatureXtract is an all-in-one complex feature extraction and 3D modeling software system developed with the defined objective of improving the process workflow experience. Its sole purpose is to maximize the efficiency of modeling by providing accurate and easy-to-use precise software tools. Through its tight integration with geo parameters and standards, 3D FeatureXtract allows users to explore, discover, and accurately reference 3D spatial content in their data and truly forge ahead with advanced modeling tools. The purpose of this document is to provide users with an easy reference tool for extracting simple buildings within 3D FeatureXtract. For additional information on the functionality included within this tutorial you can always consult the User Guide which can be accessed through either the Start Menu or through Windows Explorer. This tutorial uses the project file that was created within the first tutorial, Project Setup. BEFORE YOU BEGIN: Ensure that you have already installed and licensed 3D FeatureXtract. For any assistance on the installation itself you may always consult the installation document. The software can be downloaded from the link below: For this tutorial (and others) we utilize the Raleigh Demo Dataset. Please be sure that you have downloaded these scenes. If you have not done so already, you may download the files from here: If you completed the initial Project Setup tutorial you may load this project and continue on. Otherwise you will need to setup your project, import the data and set the corresponding coordinate system before continuing. Launching 3D FeatureXtract After downloading and installing 3D FeatureXtract you may launch the software through two (2) different means. You can either launch the software through the Start Menu, or if selected during install, you may launch it through the Desktop shortcut. Page 1

2 Simple Rectangular Building Once the software is launched go to the HOME tab and select the Layer Manager. This will now display the vector layer that you created in the initial project setup. In order to make the layer viewable and editable please select the two radio buttons. The right radio button is to display the selected vector layer and the left radio button is to make this vector layer editable. Only one vector layer can be editable at any given time. You may now ensure that the GlobalDEM.tif file you previously imported is selected as the Source DEM which is located in the upper right hand corner of the HOME ribbon. In order to load imagery into the viewers you may hold your cursor over the thumbnails located in the imagery preview pane. Once you locate the image SA1_058_59hr.tif right click on the thumbnail and choose Send to Left Viewer. For the right viewer locate the SA1_058_60_hr4.tif, right click on the thumbnail and select Send to Right Viewer. Page 2

3 Now that the images are imported into the viewer s we need to locate the white warehouse which is located within the red box in the left viewer seen above. With the warehouse located you may now begin to digitize the building. Select the Feature Extraction ribbon and select the Polygon option. You can then start your first point. Hold the CTRL button and click the first point. For simple buildings you can draw the points either counter or clockwise. You may also draw within either the right or left epipolar space. After drawing three points you may finish the polygon by right clicking the mouse. Since the left and right image are generated within epipolar space, after drawing a polygon the other viewer will display the polygon off centre. In order to create the height elevation properly this needs to be corrected. Page 3

4 This image cannot currently be displayed. To correct the shift ensure that the Feature Extraction ribbon is active and select the Move Epipolar button. You may now select the shifted polygon in the right window and move it so it lines up with the building. Since this is created within the epipolar space it will automatically move across the epipolar axis. Now that these coincide the software will assign an elevation value to the polygon. In order to create the 3D buildings you may now select the Extrude Polygon(s) button. This will created the 3D structure in both viewers to the base of the DEM. Page 4

5 The extrude button will place the 3D structure to the base of the DEM but sometimes you need to modify the Z-axis. To do so simply select the base polygon feature of an image and the Move Z-Axis icon. You may now move the Z-axis either higher or lower. A good technique is to move the Z-axis so that it aligns with the building base in the viewers. Pitched Roof Building You may now locate a building with a pitched roof. Similar to the first building simply digitize the building by drawing the four vertices, move the epipolar but do not extrude the polygon. Now select the Build Roof button, followed by the Pitched option. This will open a new panel where you can specify characteristics of the pitched roof. By adjusting these values the roof pitch should align with that in the image. Page 5

6 You have now created the pitched roof, but might notice that the end of the roof is not properly depicted. In order to change this you simply need to select the Move Freehand icon and move the point (circled in the print screen) of the pitched roof to properly reflect the end faces. Once you have moved the end faces to match that of the image it should look something similar to the print screen seen above. Page 6

7 To complete this pitched roof building you may now create the 3D structure by extruding the image. Similar to the rectangular building you previously created select the Extrude Polygon(s) icon to extrude the building to the base DEM and adjust the Z-axis accordingly. You have now successfully extracted and created simple 3D structures within 3D FeatureXtract. Please be sure to save this project as it can be used in the next tutorial, Complex Buildings. If you have any questions or concerns about processes included within this software, please be sure to contact Page 7