Understand what a point cloud and laser scan are.
- [Instructor] For this lesson, you won't need to open up a project. What I want to do is describe what a laser scan is, what a point cloud is, and what a scan project is. In the upper left hand corner of the screen, we can see a big blue box and it says scan project. Now this is actually a button. We don't want to hit the button, but I'll move my mouse up to the illustration above the word scan project, and this is an illustration of a typical laser scanner.
At the bottom of the laser scanner, there are three legs. So this is a tripod that the laser scanner is sitting on. Those legs can be adjusted so that the laser scanner can always be at a nice, even plane so it's always looking straight ahead. Then the laser scanner on top will begin to go around in a circle, a full 360 degrees. As it spins around in a circle, it casts out a beam of light. That beam of light hits the objects right in front of it, and then that beam of light bounces back to the laser scanner again.
The laser scanner measures the amount of time it takes for the beam of light to leave the box, hit the object, then come back again. Since light always has the same speed, that means that the laser scanner can know that if it took a certain fraction of a second to go from the box to this object to back again, it can then measure the distance away that that object had to be that the light bounced off of. Once it does that calculation, it puts a point within the software in three dimensional space.
To see those points, I'll just click inside of my view then zoom in. Here we can begin to see individual points, each one of these individual black or colored dots. Each one of those is a point in the point cloud, and as I said a moment ago, those were registered by the fact that the laser scanner was sitting there on the site. It shot a beam of light out. It bounced off an object, came back, and that point is the estimated spot where that beam of light bounced off of the object.
The laser scanner does this thousands of times a second, measuring everything that it can hit a beam of light off of as it makes its 360 turn on the tripod. Now for a project of this size, just putting the laser scanner down in one spot won't be enough because there's too many things that can get in the way of that beam of light. So to do a scan of a building of this size, you would need to pick up the laser scanner after it's done its full 360 degrees, then move it to another location, sit it down, let it spin around again, pick it up, sit it down at another location, let it spin around, and you continue to do this until the laser scanner can hit the faces of all the different objects in the room.
All those different spots where the laser scanner was picked up and sat back down again are considered different scan locations. Each of those scan locations are then merged together to make one point cloud in what's called a scan project. So what ReCap does, if I zoom in here, is that it will take that information from the laser scanner and then display each of these points. All the points when they come together make up what's called a point cloud.
Each one of those points regenerated from an individual scan location where the scanner sat inside of the room, and all those scan locations come together to make a scan project.
- Starting a new scan or photo project
- Navigating the menu
- Importing data
- Recovering deleted points
- Selecting and sizing points
- Measuring distances and angles
- Setting outer limits
- Adjusting color, lighting, and the background
- Scanning regions
- Saving and exporting a project