For the building of a three-dimensional model fragments, comprising the object surface, should be aligned as close as possible. The alignment is taking place based on the shared unique geometry (relief) of the object surface. It is problematic to perform registration of flat surfaces, because there are no common marks on such surfaces to align scans.

When scanning with markers or on the rotary table the model looks whole, however, registration is not accurate enough to build a single model. If you are scanning without markers and without rotary table, pieces are completely separate.

Feature of merging layers (scans, fragments) is used for their match before constructing a single model and is situated in the Registration menu. A scheme representing the scan merging process is given below. Depending on the type of project (scan method) the processing of a model is different. Use the scheme to decide which functions are needed to process your particular project.

A detailed description of merging functions is given below.

<aside> <img src="https://s3-us-west-2.amazonaws.com/secure.notion-static.com/ece107e3-8d21-41f8-9948-06f5f0544f3a/blank.png" alt="https://s3-us-west-2.amazonaws.com/secure.notion-static.com/ece107e3-8d21-41f8-9948-06f5f0544f3a/blank.png" width="40px" /> Before using any of the registration features remove the artefacts and unnecessary items that do not belong to the row for the correct operation of merge algorithm.

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Auto registration of scans is used to align separated and randomly oriented scans. Such scans are obtained when scanning without markers or turntable.

To start the merging select the group (folder), containing a number of scans to be aligned, in the project tree and then select Automatic registration.

During the registration process the software analyzes the shape of scanned surfaces and consecutively attempts to merge them together.

To combine several aligned groups into one group Auto registration of groups is used. The groups must have common surfaces (belong to a single object) and consist of previously aligned scans.

Select the groups to be aligned in the project tree, using Ctrl + LMB and press Auto registration of groups.

When register groups, the order of selection is important. Joining occurs to the first selected group. Two groups, two scans or a scan and a group can be aligned using Manual registration. Approximately matching these objects will be enough for a successful registration. This can be done either by selecting common points on the surfaces or by manually moving the objects roughly into position.

To align by points use LMB and Alt to select the common points of the fragments (at least 2 pairs) and press Enter.

For manual alignment, select fixed (after confirming the selection, it will be highlighted in blue) and floating (after confirming the selection, it will be highlighted in red) fragments, then at the bottom of the screen, manually, using the mouse while holding down the Shift key, set the floating fragment to the position in which it should be located and press Enter.

The functionality of manual alignment by markers is located in the “Registration” widget and available in the normal design mode and in the Processing mode.

The functionality is intended for preliminary registration by markers of single scans or pack of scans with similar markers. In Processing mode, you can combine several base grids or different projects according to the indicated similar markers. As in manual geometry matching, you need to set a target and a moved groups.