Representation | 3D Scanning

4 / 5 A short diary of five introductory software sessions, covering Rhino (two parts), ArcGIS, 3D Scanning and Adobe After Effects. Delivered via The University of Greenwich as part of the Landscape Representation module within the Master of Landscape Architecture program.

The Task

2.5 hour demonstration workshop of how a 3D scanner works. There are two components to the result: firstly a scan of the physical geometry, and secondly a scan of the colour information i.e. a photo of the space, taken in full panoramic.

Key Notes

A 3D scanner:

  1. Scans what you can see…. that is to say, it travels through glass, but can’t see through objects. Always do more than one scan of any space for this reason. The best place to hide is behind a wall, or under the scanner!
  2. Requires at least three scans,  with correct setup needing to be able to see scan site #1 from #2, then needing to be able to see #2 from #3, etc.
  3. Set at the maximum resolution it will take about 2 hours per scan and it’s highly unlikely a computer will be able to process multiple files: so reduce the settings. Low scan in comparison will take about 5 minutes and the capture is still very high resolution. Only use the highest settings on very small spaces.

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Scanner

 

 

Scene software allows you to:

  1. Make either a point cloud model (which you can’t edit in 3D software), OR make a Mesh (which is really easy, and means you can then manipulate the file further).
  2. Follow a clear workflow bar that sits across the top of the software program. The ambition is to make all 3 boxes in ‘Project’ (tab 1) turn green, and at that stage, the process is finished.
  3. Select the ‘Registration’ tab (see pic), where you can stitch all of the scans together. Here there are 3 options, being ‘Auto’ – which may or may not work; ‘Manual’ – which is very easy: matching viewable elements; ‘Visual’ – which is organising parts. We tested ‘Manual’.
  4. In the ‘Manual’ option, pick the top image from each scan > mark targets (see pic) > mark a point or a plane > keep marking > the top button goes green. Points and corners of things tend to work better than planes.
  5. Navigate around a rough model in the ‘Explore’ tab, which will be a lower resolution on screen than what is actually captured. Use an auto-clipping box to quickly tidy up the file: move and rotate this to fit. You can use as many clipping boxes as needed.
  6. Finalise your master image via the last option on the ‘Create’ tab. Typically keep the settings on the default options, then this stitches all the scans together.

landscape architecture

landscape architecture

 

Export considerations include:

  1. File types are typically .stl – for 3D printing; .ply – not very commonly used; .obj – the universal file, can be used in any software (obj = object)
  2. Point cloud is good for background fills. In last ‘Export’ tab, export project point cloud. Studio Max doesn’t work with .pts (point cloud) file, but export this then open up Recap, scan project, open and save as .rcs (Revision Control System) file.
  3. Point cloud option can’t be used in Rhino, but can be used in other 3D software like Studio Max (Autodesk 3ds Max) and Blender.
  4. The settings when making a Mesh have the option to make it watertight, which would then be suitable for 3D printing…. But remember it’s 1:1 and will likely morph some of the shapes. Mesh turns your scan into lines and triangular faces. Mesh Selection > mesh clipping boxes > will turn yellow. Meshes > right click > export > save.
  5. A Mesh should import into Rhino easily, however, don’t apply lighting as this is already baked in from the photographs. When viewing the model in Rhino Render mode, it will retain the photo information. Note: this is if you have scanned with colour. You can turn colour on/off, and without it will give whitey grey overall finish. Turn Mesh Wires on/off in display settings of Rhino.

 

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