RealityCapture can work only with ordered point-clouds. These point-clouds are mostly created by terrestrial laser scans (like Faro, Leica, Trimble). But it is possible to create ordered point-cloud from unordered point-cloud and there is how.
1. Intro in RealityCapture and general RealityCapture point-cloud requirements
In this section is described basic setup in RelityCapture for good working with laser scan point-cloud. These setting are in Reconstruction tab -> Reconstruction settings -> Laser scans
- Minimal distance between two points - points, which are closer to each other as this value are omitted (this could cause problems if the laser scan is in different units then meters)
- Point-cloud cropping radius - any point which distance is larger than 150 m from zero laser scan station is omitted
- Minimal intensity - RealityCapture is working in the intensity spectrum 0 - 1. If the intensity values are more than 1 it will cause a problem with point-cloud
These values are in meters (not intensity). It is important to have all of your scans in meters (not feets or miles). You should consider about all of these parameters before using your point-cloud in RealityCapture.
2. Scaling in CloudCompare
For the quick check if your point-cloud is suitable for RealityCapture or not you can use CloudCompare. After point-cloud import, the first thing which you will notice is the rotation of point-cloud. In this case, if you use different views, these should be correct. We want to have an ordinary oriented point-cloud (up is real up).
The second thing to check is if there is some TLS/GBL (scan position). If not, this means, that the point-cloud is unordered.
The units of the model we can check after clicking on the point-cloud. If the box dimensions are in thousands, then it is not good (laser scans have mostly range hundreds meters). On the next image is how it should look.
If these values are not in meters, we can scale the project in CLoudCompare. Go to Edit -> Multiply/Scale and set the correct scale to transfer values to meters. Then we can save this point-cloud.
3. Creation of virtual scan positions in Faro Scene
In Faro Scene we will create new project. Through Import tab we import our scaled point-cloud. Then we need to process our scan.
What we want to do is creation a scan point-cloud. It is in Configure processing settings.
After processing we can go to Explore tab and by right click on the point-cloud -> View -> 3D View we can see bad orientation of point-cloud (similar as in CloudCompare). What we want is, that if we show Top view, then we will see the top of the point-cloud, not other site.
To change this click on the point-cloud and choose Properties -> Transformation. There is possible to change rotation angles to wanted (where top view is from top, etc.). Also we can do some adjustments to position.
After this we want to create scan position/s for this point-cloud. We have to move to the right place (where should stand scanner) and create a virtual scan with High resolution and enabled point interpolation.
We don't want to crop anything from the point-cloud so this position should be located near to position of original scanner. If there will be some kind of overlap with front and back point-cloud, the resulted point-cloud will have only the first viewed points. If the point-cloud is created from more scan positions, we simulate also scanner movement and create virtual scan for each position.
After creation of all wanted virtual scans we can export them.
Set correct maximal distance value (150 m as it is in RealityCapture) and choose E57 format. Keep value 1 for subsampling.
4. Import into RealityCapture
After these steps you can import this ordered point-cloud into RealityCapture. Depending on your point-cloud, the settings will look like this:
Use Unregistered, because you want to register this scan with other scans, Feature source as Color (when there is not intensity) and also Intensity channel type as Image.
After import you can work with this point-cloud as ordered.