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Claes Lundstrom

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Posts posted by Claes Lundstrom

  1. 26 minutes ago, KenH said:

    Hi everyone.

    Can anyone tell me how I can generate keyboard shortcuts on my MacBook Pro when I am out of the office. 

    I know Control Five will give me top plan view but I don't have a shortcut for an isometric view. I find its a pain to go to the top of the screen click on the Current Screen arrow to list the different views and then have to go through the entire process again if I want to then show the design in a different ISO view.

     

    Any help will be much appreciated.

     

    KenH

     

    My solution to this rather annoying shortcoming is to have a small wireless separate numerical keyboard attached when I'm on the move. 

    • Like 3
  2. 19 hours ago, grant_PD said:

    Very helpful!  Thanks.  It looks like a great reference tool and certainly worth investigating, if only to provide background for a rendering. 

    It's for sure more than an aid for rendering. In this example, a two or three minute scan in combination with the Clip Cube gives and excellent status report of how well the floor drainage is working, as you can clearly see the angle of the floor towards the drain well.

     

    A better scanner, such as the Matterport would probably give a better result, but it's never an absolutely correct result.

     

    It should also be pointed out that a conventional laser distance measuring device also comes with a degree of errors. You can try it by scanning the distance between two seemingly flat walls. Just tested my Leica at a distance of about five meters and found a fluctuation of 4-5 mm in a series of ten measurements at the same location. That equals to an error margin of 0.1 %. 

     

    The main flaw with laser and ladar measuring is that it does not know what is important and not. Having thousands of measuring points on a more or less flat wall or floor is a bit pointless. We as humans can instantly see where the shape actually changes, and we can therefore instantly reduce the number of measuring points to an absolute minimum.

     

    I did a lot of boat cover designs a few years back, where we tried all available methods for scanning. On a boat cover, you are not really interested in the panels as such, just where the edges are located, and this is where point cloud measuring is pretty useless. We also tried a Dutch wire based system (very expensive) and found that the internal precision it required to make it work made it drift and becoming unreliable after a while. The best way was actually to use photogrammetry using user defined measuring points. Photogrammetry uses a series of pictures from different angles and where the program compiles the data into a small number of 3D points that you can skin. 

     

    A conclusion is perhaps that each of these devices have their strengths and weak points. Laser/Ladar works best on flat of gently curved shapes, but having problems with finding precise corners. In a house with flat walls, you can use the wealth of similar points to identify a wall or floor and then let the CAD program find the joints. The trick is to find the right combination of tools for a given task. 

     

     

    Drainage scan.jpg

    • Like 2
  3. 45 minutes ago, grant_PD said:

    @Claes Lundstrom how accurate was the overall scan?  In my case I'm looking at verifying things like position and size of an electrical outlet on a wall from the model.

     

    My guess is about 1%. Heights are a little more accurate. You can't measure something like a kitchen for production design where you cut everything to measure, but it has proven invaluable as it gives a lot of details and where they are located. Great for creating cost estimates. In the example, one of the tasks where to locate plumbing and ventilation, where we did not have any documentation at all. The architectural drawings from 1939 where a bit sketchy and the building had some changes made over its 80 year plus lifetime. I'm actually surprised how useful it has been scanning with the phone, and I suspect every contractor will have something like this in their standard tool set some time very soon. 

    • Like 2
  4. On the subject of argumented reality, I have tried Adobe Aero, and it seems to work with files from VW, TouchCAD, Scaniverse and Keyshot on both the Mac and on iPhone. The picture is from an iPhone.

     

     

     

    688134873_TouchCADmodelbyAdobeAero.thumb.jpg.9dff362d3b4111f512d6ae59c3cd4322.jpg

    • Like 1
  5. 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. 

     

     

     

    1400004253_Scannedchair.jpg.35d5d6217c61eebcd116af581ae6d63e.jpg

    • Like 2
  6. 21 hours ago, Tom W. said:

    Are people using Lidar on iPhone/iPad to scan objects rather than buildings/topography, for the purposes of creating symbols? As an alternative to laboriously measuring things + modelling them from scratch + texturing them. I'm talking about furniture, light fittings, appliances, sanitaryware, MEP plant, etc. I can rarely find what I need in the VW Libraries so next port of call is 3D Warehouse, then if no luck there it's a case of modelling it from scratch. I have no major problem with this - I quite like doing it - but it would be a massive time-saver to be able to scan something with my phone then there it is, a ready-made, accurately-sized, ready-textured model. I suppose the only thing is that if they're meshes they're going to look bad in non-orthogonal Hidden Line views but this is the same for lots of symbols already. Well + file size of course but presumably you can simplify mesh.

     

    Is this something people are doing? I don't have a Lidar-enabled device unfortunately. I have seen some really nice looking scanned objects online. Is the accuracy better on smaller objects?

     

    Although I love what people are doing here with buildings + landscapes, for me I can't see it precluding the need for a proper laser scan + topo survey. As Jeff says:

     

    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. 

     

     

    Scan.jpg.7c8b63efbbe4dc5c4f65e08d8d7e0184.jpg

     

    • Like 1
  7. 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.

     

    669333156_Meshresolution.thumb.jpg.4352d48943baaa3d675d1f9a9ae5afac.jpg

  8. 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.

  9. 19 hours ago, fabrica said:

    this looks interesting : https://developer.apple.com/videos/play/wwdc2022/10127/ 

    parametric file seems to be brought straight into Blender.

     

    On another note, scaniverse on app store is excellent (and free!) , and the point clouds import nicely into vectorworks. 

    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. 

    • Like 2
  10. 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. 

  11. 10 hours ago, DMcD said:

    For production parts, I only do use lines, arcs and circles. However it's the VW surface extract tool which converts arcs in polylines to beziers, not me! Useful entities like rounded rectangles (for a machined slot) are converted into a mess of points. I have to go back and either redraw or manually extract the original arcs and lines profile from the model and paste it into the 2D file. Is this what we use CAD for? Not me!

     

     

    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. 

    • Like 2
  12. 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. 

    • Like 3
  13. 57 minutes ago, Tom W. said:

     

    Is there a difference scanning on an iPad compared to an iPhone does anybody know? I own neither nor have ever done so. Just wondering if any advantage to doing it on iPad in terms of range/speed/device getting hot/etc. I can't really justify getting an iPhone right now but could perhaps if it was an ipad...

    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.

    • Like 2
  14. 1 hour ago, Tom W. said:

     

    This is what I was interested to know: how you go about converting the scan into a DTM.

     

    Is there a way to use the Analysis Tool to quickly place a grid of 3D Loci on the surface of the object + then create the Site Model from these, rather than the manual tracing method you describe...?

    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.

    • Like 3
  15. 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. 

     

     

    Skärmavbild 2022-01-28 kl. 10.38.58.png

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