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Claes Lundstrom

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Everything posted by Claes Lundstrom

  1. The biggest limitations when scanning objects with an iPhone, such as the Eames chair, comes on the skinny parts, for example the foot and armrests. Bigger more solid chunky objects typically works fairly ok I would say. In my example, a 250 year old chair, the seat works fine, whereas the skinny and more intricate parts fail. The problem with it is of course the combination of being skinny and having a very intricate and detailed shape. Another disadvantage with scans in general for a symbol is that the model becomes much bigger. A good symbol should always have as few elements a possible, especially when you insert many on a bigger model. Keep it as simple as possible while maintaining a recognizable shape. Scaniverse.mp4
  2. On the phone level, it can not be used directly to measure for example kitchen cabinets. It's simply not accurate enough for precision measurements. It is however useful for quick price estimates and an excellent piece of documentation. Another major flaw with scanners is that they generate huge files where almost everything consists of junk info. As an example, imagine a very simple table model, represented by an extruded rectangle representing the table top and four small extruded rectangles for the legs. The parts can be defined mathematically by a very limited number of coordinate data. Most scanner software on the other hand, needs to measure a huge number of points just to be able to estimate where the key data points (the edges) are located. The fundamental difference is that the human computer can instantly figure out where the edges and boundary are, whereas most scanner software can't. On more organic shapes things swing a bit towards scanning. Manual modeling can still generate much smaller models, but it requires way more skill and craftsmanship to get there. The example is probably beyond what most CAD designers could achieve and it would take quite a lot of work. The scan took less than five minutes with an iPhone 13 Pr. The result is surprisingly similar to the original (the picture to the left was placed next to the original within the scanning software). The model was also accepted without any problem by the 3D printer software and came out fairly good on a simple $200 3D printer.
  3. I have used my iPhone too and found it quite useful. In this example, I tried to illustrate potential drainage problem against a house wall. Here is another example where I made sure it was safe to drill a vertical hole in the middle of a lot of piping and equipment, by placing two different scans from two different floors on top of one another. Note how well the walls aligned.
  4. I think meshes are what the are, and are not really affected by these settings. NURBS based models are different as they enable you to calculate pretty much any mesh resolution / smoothness within a given surface, though in VW it means high, low, and medium rather than using numerical settings, and as a universal setting rather than an object specific setting. The picture shows an example from another CAD program, where such settings exist, and where one side consists of 28800 quads and the other side of 81 quads, and I can individually change it back and forth at any time and when I need to. I personally find such settings invaluable. Technically, there is no reason why VW could not have it too, but there isn't.
  5. Generate a separate rendered water surface that looks like thet type of water you want, and use an extraction of that as a texture map in the shaded version. It will of course not look as good as a full rendering, but the Shaded mode was not intended for that type of use.
  6. Scaniverse is also my absolute favourite after have tested several similar programs. Scaniverse works very well with VW in several file formats. Using a points style format works best for terrain models. I mostly use OBJ for textured models though.
  7. Accuracy is, according to their web site, +- 0.5% on a 12 ft long line, so +- 18.3 mm. So, in my experience it does not seem better than the lidar apps I have used for the iPhone 12/13 Pro. Seems rather expensive relative to what it does.
  8. I agree that it would be very useful to be able to control the number of points (beyond high, medium and low), and exact behaviour of a given curve. In my main 3D modelling program, I can set it locally for each given element, part of an element, and numerically to whatever I find relevant for any given task. I find it extremely useful, and could probably not live without it for my type of work.
  9. Have done a lot of such work. The problem is often in the other end, that is, many of the programs used for controlling CNC machines have severe limitations. The software is often simplistic and often ageing. I therefore suggest keeping geometries on a very basic level. In 2D, it typically means using lines, polygons, and arcs to define things. Avoid Berzier and spline curves. Avoid symbols and groups. Avoid using filled surfaces, and for example using Clip Surface to define a hole in a closed polygon/polyline shape. On polylines, only define shapes using straight lines and arcs.
  10. I think the liar is the same on iPhone 12, 13 Pro and iPad Pro. It's basically a matter of taste using a smaller or bigger screen vs how easy it is the bring it along at any give time. A smaller screen works fine for me tough. I have the bigger iPhone 13 Pro model.
  11. There are many apps on Appstore doing this. I checked five or six and decided on Scaniverse as my personal favourite. It's also free, believe it or not. Is it difficult to use? I bet you will get something reasonable good out of it in your first try. It's fairly similar to creating a movie. You get white and red stripes where it still misses data. Just move around with gentle movements and watch was happens on the screen. You need to practice a few times to know how to get the best result, but it's fun and easy. Skinning the model takes a few seconds, in any event less than a minute, after which you can look at the result on the screen in full 3D, including spinning and zooming. You can trim and rotate the model in the app, and even generate a movie or a still shot from any view. Then save the model if the preferred format. I have a Mac, so a quick Airdrop from the iPhone or iPad is the quickest way to export to the Mac. Takes seconds. OBJ gives the best rendering, whereas PLY works best for Digital terrain models. The Ply importer allows you to define the number of points to be used with a slider. Lower res may be good enough. It's a bit like using a well used piece of soap instead of a new one having sharp edges, or using a more or less blurry image to represent the shape. In VW, you import OBJ as OBJ and PLY files as a Point cloud. The sample model contained 469204 points.
  12. Though I would try the other formats supported by the iPhone scanner program. Besides OBJ, it also supports PLY and FBX. Not sure about FBX by this is what came out of the PLY version, when converted into a Digital Terrain model. The model was about 7 megs. The input as such was not as pretty as the OBJ, but the DTM thing working is a plus. Of course, it freaked out a little by the house and resting walls and where there was a steep rock wall, but not bad. Measurements seems t be right too. It only took a few minutes to get to this, plus the five to ten minutes it took to scan the site. Not bad for a phone? I even managed to include my feet here and there by scanning myself.
  13. The scan was more like 10 minutes. You don't get mm precision, for the most part more like within say 10 cm. Heights seems to be more accurate for some reason. To check I measured a seven story stair, and compared it to the real heights and the heights where off by something like 2-3 cm, so the fluctuation was not clearly distinguishable from fluctuations of the eighty year old concrete house. At the most heights where possibly short by say 2 cm on a 2.7 meters height of each floor. The scan was essentially done by walking from the top downwards in the stair, at say half the speed I normally use, while gently moving the camera back and forth. Time, say five minutes at the most. The picture shows a hybrid of scan and measurements. The back side drifted a little in shape due to bad access to a corner. When scanning large objects, it's important to do it using slow and gentle movements. Limitations. The lidar can only measure up to about five meters, so tall buildings are impossible without a drone. Size, just to mess with it, I had a walk around a small local lake, having a circumference of about two kilometers, As you can see from the second picture, it started to get lost about half way around it, but when I made a copy of the cans and rotated it around the point where it got lost, the second part actually worked fine. I placed it on top of a satellite map and the result was surprisingly good, considering that it's not really a measuring device, it's a PHONE. I checked regularly against the water surface to see if it drifted in height, and it basically didn't. It also freaked out completely at about 1.7 of the 2 kilometers, though the data wasn't lost. It just slowed down to a crawl.
  14. I used the this manual method as VW does not seem to like meshes having a couple of hundred thousand triangles. As I mentioned, I generated a flat rectangular 3D polygon and used that as a working plane. The trace takes place that the intersection between the flat plane and the 3D model, a bit like something sticking up on a water surface. I started at the lower corner of the house with Z = 0. I then went to the top (not top plan) and traced the contour around the intersection between the flat plane and the 3D model using OpenGL rendering (or whatever it's called now). I used 3D polygons but it can just as well be 3D loci. Also important to do the tracing in a different layer with no intermediate snapping going on, as VW then freaks out completely. Once one level is done, you simply move the flat plane up some distance, in my case I used 0.5 meters, and traced it again. Remember to move the working plane to the new level. Etc. The result was indeed a site model. Details such as trees are easy to insert when required.
  15. My comment was perhaps not intended to be all that seriously for city planning 😉 The iPhone can be surprisingly useful for smaller projects. The movie was just for fun and was actually created by the iPhone program itself. The purpose of this scan was to analyse a drainage problem on a 30 x 15 meter area. The scan took say 5-10 minutes as the site was rather steep and slippery. The model imported fine into VW though I hade to fit the YZ from this particular program. Converting the model to a DTM seemed to take forever, so instead I placed a plane at a given height and traced the intersections manually in a separate layer not using snapping. I then moved the plane a given distance and repeated the procedure until I got a series of 3D polygons, which was used for creating the DTM. I also did an illustration of the shape using a series of vertical grid surfaces to visualise the shape to the non technical people.
  16. ... or you can use a poor man's drone, an iPhone 13 Pro 🙂 and Scaiverse Poor Mans Drone.mp4
  17. Using lofting of cross sections can be a nightmare in most NURBS based programs, and VW simply doesn't handle NURBS editing very well either, compared to most standard 3D CAD programs. No disrespect intended. VW's inability to nudge control points, and why you can't edit any number of control points in any number of objects at the same time remains a mystery. In my professional boat design program, I can easily tweak 500-1000 NURBS objects at the same time using a random selection of control points, and get an instant update of the lines drawing at the same time. Given the use of VW, you my consider using the following method: 1/ Generate some curves along the length of the boat, say three. 2/ Loft them into a a surface. Convert it into an interpolated surface having four by four controls in the grid (or thereabout) . 3/ Adjust the shape so that it looks reasonable. 4/ Add sectioning to see what the shape looks like. 5/ Repeat step 4 & 5 until the sections get close to the original cross sections 6/ Extract the cross sections to generate the updated buck shape cross sections.
  18. The three point arc mode in the Reshape tool creates arcs like in the picture, where I exaggerated the shape to illustrate it. In reality you need to fine tune it more. This typically works best of the arcs as they are seen as just arcs by many cutter being next to one another The Blue circle is just one object being on top of another, which works better that the second option, where there is a physical hole in the rectangle. You can however achieve this by exploding the model before exporting to the cutter. The fist option is what I typically use within VW as its much more logical.
  19. I have for sure tested it indoors too, and even though it wobbles a bit and generates rounded corners etc, I'm still amazed when I scan from room to room. You need to wing it a bit and double-check key measurements, but the voids generated by walls are clearly there and they are reasonably correct.
  20. Nobody expects it to be as good as the pro equipment, but for smaller projects it may very well be fairly usable, and for getting rough estimates. It was however way better than I expected. And having it in your pocket at all times is great, and its quick.
  21. Yes it comes in as a textured polygon mesh, so it can be used as a solid. This can be handy for trimming off unwanted objects, and things that don't scan well, such as shiny and reflective objects, and thin objects like branches, shrubs and bicycles to mention a few examples, and when the model starts to drift a little. In this case I caused such a drift by jumping down to the sidewalk, which wasn't a good idea for the scan. It is a fairly steep model and was rather slippery. It basically consists of polygon triangles, but it's usually not a good idea to explode it, as VW moves into a crawl. Most likely, you can use it to create a digital terrain model too, yes. Should also be mentioned that the program used exports as FBX, OBJ, GLB, USDZ, STL, PLY and LAS, so there are plenty to choose from when it comes to importing to VW. What I found useful was that you can render the model in OpenGL and use the textures to identify known points, for example trees, fences, etc.
  22. Speaking of scanning terrain models. I played around with the Ladar features my new iPhone 13 Pro. Surely, it could not be used for scanning terrain models, right ? Ehm, after having tried it, I'm not so sure. The 20 by 36 meter model took ten minutes to scan, by walking around waving with the phone back and forth (the Ladar can only see about five meters at the time), and when I placed it over the map it actually fitted surprisingly well. Heights where totally reasonable too. Imported without a hitch into VW. WHAT!!! ? It's just a phone!!?? Furthermore, I was curious to see how far I could go in size without the system freaking out completely, so I took a walk around a small local lake, having a circumference of about two kilometers, walking on a park gravel path, measure the water level here and there. It turned out that the system freaked out around 1.8 kilometers, though it did not crash. I imported the model into VW and placed a satellite picture map over it. Again, the scan matched the path very well up to about 1 kilometer, and then started to drift a bit. Made of a copy of the scan and rotated it, at the the rest was fine again. Somehow, it managed to keep track of the heights relative to the water lever across the scan. What can I say, but what? and wow! I used a scanning program called Scaniverse, which was a free download on App Store.
  23. It's not that difficult. A few basic rules when exporting to 2D CNC though: Keep it as simple as possible. Use text code instead of binary. Do not use things like symbols, fills, etc. Avoid Splines, Berzier curves, NURBS curves, etc, convert to plain polygons at reasonable resolutions. If curves are used, be sure to use arc based segments. Object types should be restricted to lines, circles, arcs. Decompose polygons having for example holes etc inside using Clip Surface. For milling, where the tool as a diameter, be sure to place objects inside objects in a different class or layer, as they should cut from the inside instead of the outside of the contours. Cuts and Incuts are not the same thing there. Check if the receiving program uses some sort of industry standard layering system, and if so, follow it.
  24. Speaking of ladar scanning, I played around with my new iPhone 13 Pro to see what it could do. I realised that it could detect heights on a slope, so I made a test on a 35 meter long area basically for the most part covered by tarmac. I really expected the result to be a total mess and failure, but much to my surprise it came out better than expected. The screen dumps are from the phone directly, but I could export the model as OBJ into VW, where it looked the same. The slope looks right. I measured the height of the retaining walls and concluded that they where about 50 cm high in the model, which they are in the real world. Cars, bicycles and shrubs caused a bit of a mess, but then can easily be removed. You do get some steps here and there, but on the other hand you are looking at a 100 000 triangles, so an average should be fairly ok. You can also ignore and remove the stuff that looks wrong. The scan took say five or ten minutes. I used a program called Scaniverse, which was a free download on Appstore. The model is a mesh, so it should be processable with DTM, I think. The question now is, is this actually feasible to use in the real world ? After all, it's just a plain standard PHONE !!!!
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