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.

 

Representation | Rhino Intro I

1 / 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

3 hour practical workshop, creating 3D shapes in Rhino. The final output was to build a pier, lighthouse, terrain, path and contours, that could be further modelled in Rhino as well as taken into Adobe Illustrator for digital enhancement.

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Key Basic Commands Used

Creating 2D and 3D shapes: Polyline, Spline, Extrude, Circle, Pipe, PlanarSrf

Progressing from individual objects: Split, Join, Rotate

Shortcuts to save time: Copy, Paste, Move, Offset (ThroughPoint)

Developing digital images: Make2D

5 New Commands I Didn’t Know Yesterday

  1. Loft | Really easy way to fill a space between two joined curves to create a surface. Previously I’d been doing this manually with the 4-point surface command button. See example: base to the top of the lighthouse.
  2. Project Curve | Quick command used to draw a shape on one plane and then accurately project it onto another existing object, particularly useful when that object has curved sides. See example: the path which was drawn on C Plane then projected onto the varied terrain.
  3. ExtractSrf | I didn’t realise the strange geometric effect I often created was an error sign showing that two surfaces were meeting, and wouldn’t be accepted by a 3D printer. Extract Surface is a useful command to quickly delete specific sides. I had been using the Explode command previously, which creates extra work. See example: removal of the base at the lighthouse door.  
  4. Rebuild | A flat ground plane for the terrain was created with a 4 point surface. Rebuild command (with points visible) provides a default grid of an extra 10×10 points to manipulate. See example: dark green terrain with rolling hills.
  5. Project (a mode not a command) | Hadn’t been aware of this useful option (checkbox) to assure that you are always drawing all points on the C Plane. Switch off, and then work again in perspective to move the correct shape to the required location.