When you create a mesh, you typically use the Mesh Buildup Wizard. If scan data is constituted by line-type point clouds, however, boundaries are not easy to maintain in their original shape while you generate the mesh.

If you manually triangulate using the 3D Triangulation command in the Addins menu, you will get better a result than the automatic Mesh Buildup Wizard method, as shown in the image below.

Method:
1. Before you apply triangulation on line-type scan data which is already aligned by a scan device, we recommend that you accurately align the scan sets again in the software. Select the Align button in the bottom pallet menu, or Click Tools > Scan Tools > Align in the menu.

Use the Global And Fine method with the “Apply Only Small Transform” option as shown in the below image. This option considers that the initial alignment is already done and accurately aligns scan shots, removing gaps among scan shots via small transformations. Plus, if overlapped regions have a planar shape, the alignment may slide along the planar area. This option prevents such featureless scan shots from sliding during alignment.

2. Apply the Addins > Combine command to make a single scan data set.

3. Click Add-ins > 3D Triangulate in the menu and check the “Assume Vertices Are Densely Placed Along A Direction” option. Especially, when you try to triangulate line type point cloud, this option is appropriate for keeping edges or boundaries as shown in the below image.

4. If necessary, execute the Enhance, Global Remesh and Fix Normal commands in Mesh mode to get a mesh which is well optimized and featured.