In this tutorial, I will review some basics for drafting from a point cloud as well as a few tips and tricks.
The first thing I will do is create the outline of the main building. To do this, I will isolate the building from the rest of the data to make it easier to visualize and draw on. Open the Point Cloud manager under the Point Cloud toolbar. This manager allows you to view and manage point cloud regions. In here you can control the visibility of point cloud regions, shift the perspective to the point of the scan, and search and rename regions of the scan. I will toggle the boxes besides each region to hide the visibility until only the buildings region is displayed.
Next, select the point cloud and in the Cropping tab, select Polygon. I will crop down as close to the building as possible and select to keep the Inside. To view all of the data once more, simply select the Uncrop All command in the top ribbon once more.
Another trick to bring more detail to this outline is the colour map. Under the Point Cloud visualization tab, you can toggle the visibility to Elevation. Select Color Mapping and a new dialog will appear where the colours can be set based on the elevation of the point cloud. I will change the colour scheme to Spectrum to show a broader range of colours. Now, only the colour red is displayed, this spectrum has been applied to the entire point cloud. To change the colours of the building, we can change the range of colourized points.
Uncheck the Apply to Extents of the Point cloud and here, the maximum and minimum elevation can be reset. As shown here, the building is between the elevation of 1620 and 1630 so I will reset the maximum and minimum elevation. This is a useful tool to see different details in the building.
From the top view, I can see that the building corners are marked by the blue outline of the building. To better define the building corners for linework creation, I will crop out the bottom half of the building. Firstly, toggle the view to a side view and select the point cloud. In the top Point Cloud ribbon, select the Rectangular cropping tool. Highlight the bottom half of the building and keep the point cloud Outside the selection.
Once complete, select Uncrop all in the Point Cloud ribbon to display all point cloud data. To better visualize the data, I will toggle the visibility to Intensity mode. To do this, select a Point Cloud region and in the top ribbon under Visualization, select the drop down and intensity. I will change the transparency to 75 for easier viewing.
From here, I can rotate the view and create linework and features for flow lines, road edges, vegetation and all other topographic features.
