Apologies in advance for the length of this post, but I promised the OP that I would detail my point cloud workflow for a straightforward project. The reason I use points clouds is partly to help create visuals, but mainly because their accuracy enables us to create structural glass extensions that must fit snugly against elevations that are often a long way off square, such as very old cottages that have walls which can be literally 150mm off vertical over a typical 2.5M height. A quick laser scan allows me to detail the large glass panels that fit these uneven elevations accurately, and helps me to create the visuals. I can honestly say we haven’t had a single glass panel that didn’t fit perfectly since we started using digital surveys about 4 years ago.
1: I usually scan a client’s property on my first visit using our Faro 3D Laser Scanner to capture the buildings current ‘as built’ condition, even though part of what I am scanning will usually be replaced.
2: I usually provide the client with a free visual which I create from the scan using SketchUp and Vray. I used to model everything from the point cloud and render it with Vray, but now if I can get the right site photo, I just model the new glass structure from the point cloud and use SketchUp’s Photo Match feature and Vray to produce the visual which is much faster.
3: Usually after my initial visit, the client’s builder needs to do some building and/or demolition work, so I will do another laser scan after that’s completed to capture the new geometry before I do my final drawings. Sometimes a single final scan is sufficient, but most projects require 3 scans or more.
4: Next, I use Faro’s Scene Software to process, register and clip the individual scans into a single point cloud which I export in PTS format which usually results in a file size somewhere between 0.5GB & 5GB
5: I then use Undet’s Point Cloud Software extension to import the point cloud into SketchUp as it handles large point clouds effortlessly and makes working with them in SketchUp very straightforward. The first thing I do is position the point cloud to vertically set the floor level then I set the red axis accurately using Undet’s Coordinate System and finally I lock it in place.
7: I then use Undet’s feature extraction utility to create a mesh from the point cloud wherever the glass meets the building, then I use the SketchUp’s Section Tools & ‘Create Group from Slice’ command to build up single line sections which follow the building’s contours exactly wherever our structure meets it.
8: Using those ‘Group from Slice’ sections I can then draw our structure to the tolerances required and be totally confident that the resulting glass will fit perfectly.
9: Once the model is finished, I create lots of standard scenes in SketchUp then produce all design, section, detail, and set-out drawings in a single Layout document usually amounting to around 50 sheets per project.
Then finally - we build it