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    [Proto] Generating Terrain from a Cloud of Points

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    • fredo6F Offline
      fredo6
      last edited by

      @krisidious said:

      would it not be simpler to make point clouds out of polyline topos and then compare the two?

      Good idea and actually I did it and obtain similar shapes, but a little rounder with the triangulator.

      The probleme however is that using iso contour cloud points is already a strong guide to the skeleton of the terrain and therefore does not validate that with scarce points here and there you would obtain a similar skeleton.

      Toposhaper is based on a linear interpolation whereas Triangulator is based on a directional polynomial interpolation, in order to avoid that each point of the cloud becomes an isolated hill or basin.

      Anyway, I am not trying to demonstrate that an algorithm can find the good solution because this is anyway wrong mathematically. There are always many solutions.

      Instead, I am just trying to check if the plugin would be useful to users and landscapers on real cases.

      Fredo

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      • fredo6F Offline
        fredo6
        last edited by

        @krisidious said:

        here's some files from when I worked at a survey company. some of them are probably point clouds. I'll have to research to find out which. maybe you'll know by looking.

        I would need something in SKP. I have no Tools to pre-process and I don't even know what are the files.

        Fred

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        • sdmitchS Offline
          sdmitch
          last edited by

          @fredo6 said:

          @krisidious said:

          here's some files from when I worked at a survey company. some of them are probably point clouds. I'll have to research to find out which. maybe you'll know by looking.

          I would need something in SKP. I have no Tools to pre-process and I don't even know what are the files.

          Fred

          Attached is a skp file with both mass points and break lines that you can hopefully use for testing. I have hundreds of such models if you want or need more.


          Alaska_NW-DTM 129.skp

          Nothing is worthless, it can always be used as a bad example.

          http://sdmitch.blogspot.com/

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          • fredo6F Offline
            fredo6
            last edited by

            Sam,

            Thanks very much, very useful.

            Actually, I have tweaked the algorithm and got the tarrain below. So I think I may finally find heuristics to speed up the interpolation.

            sdmitch Alaska.png

            There are 1986 cloud points.

            The terrain is generated with 3069 triangles. The calculation took 18.5 seconds on my machine.

            It seems to be a quite large area and quite flat except a few hill and an overall gentle slope. I had to scale in Z a little bit however to make the relief more apparent.

            sdmitch_ Alaska_NW-DTM 129 _ trg.skp

            Indeed, if you are more samples, this is welcome

            Fredo

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            • sdmitchS Offline
              sdmitch
              last edited by

              Fredo,

              These models have much more relief. They are bigger with many more points than you would normally use probably. But none of the projects I worked on were small.

              Sam


              MyDot03DTM.skp


              Dem Contours.skp

              Nothing is worthless, it can always be used as a bad example.

              http://sdmitch.blogspot.com/

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              • BoxB Offline
                Box
                last edited by

                Fredo if you want, this is a text file of a pair of Scissor handles that I recently managed to import into SU using the above mentioned Points Cloud as a CSV file of over 250,000 points.
                It was very slow but worked and I was able to view the scissors in 3D as guide points. I didn't bother with triangulating the faces as it had actually taken several hours to import just the points.
                It is without doubt overkill in the terrain context but it is the type of file people will be wanting, if not expecting, to be able to click, copy and 3d print in the very near future. Feel free to ignore it as it was something I found on the web while looking to solve terrain and point cloud imports.


                Scissors_handle_points.zip

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                • R Offline
                  roland joseph
                  last edited by

                  I think it will depend on it's capability for detail. I don't find getting the raw terrain down is very difficult. It is all the detail that has to be built into it...i.e. garden beds, curbs, sidewalks, ditches, medians, grass edge transitions,...etc. For every minute I spend creating the ground, I spend ten on the detail.

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                  • fredo6F Offline
                    fredo6
                    last edited by

                    Sam,

                    Thanks for the new models. There are a little big for the plugin, but I made some trials on a subset and it seems to be OK.

                    Below with 101 source points, generating roughly 3900 triangles to render the cliffs in 23 seconds.

                    Fredo

                    Triangulateur - small set by sdmitch.gif

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                    • fredo6F Offline
                      fredo6
                      last edited by

                      @unknownuser said:

                      I think it will depend on it's capability for detail. I don't find getting the raw terrain down is very difficult. It is all the detail that has to be built into it...i.e. garden beds, curbs, sidewalks, ditches, medians, grass edge transitions,...etc. For every minute I spend creating the ground, I spend ten on the detail.

                      My feeling is that it is better to generate first the natural terrain and then superimpose the artificial 'details', like limits, fences, roads, building.

                      Of course, these details may deserve some dedicated techniques (in particular roads and fences), but Sketchup has already a number of tools to handle many cases, with the Sandbox and with Projection and PushPull plugins.

                      I don't think it's easy (and fast enough anyway) to have interpolation generate the terrain and all details in one shot.

                      Fredo

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                      • R Offline
                        roland joseph
                        last edited by

                        "to have interpolation generate the terrain and all details" I agree that would be a trick. I use your wonderful tools-on-surface (and a couple other rubies) to build terrain. I can't guess how many square miles. I do believe your tools are the best. I am saying for me at least generating a terrain with cloud point is not very exciting. It would be selfish to say I would rather a talent like you work on other things. 😄

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                        • fredo6F Offline
                          fredo6
                          last edited by

                          @box said:

                          Fredo if you want, this is a text file of a pair of Scissor handles that I recently managed to import into SU using the above mentioned Points Cloud as a CSV file of over 250,000 points.
                          It was very slow but worked and I was able to view the scissors in 3D as guide points. I didn't bother with triangulating the faces as it had actually taken several hours to import just the points.
                          It is without doubt overkill in the terrain context but it is the type of file people will be wanting, if not expecting, to be able to click, copy and 3d print in the very near future. Feel free to ignore it as it was something I found on the web while looking to solve terrain and point cloud imports.

                          LIDAR and other techniques generating dense cloud of points require very different techniques.

                          • First this is usually true 3D (not 2.5D like terrain).
                          • Second, there is no real need of interpolation, but triangulation with the nearest neighbours.

                          I imagine there exists dedicated applications written for this purpose, in C++ or so to be extremely scalable. Obviously, that won't be the case for Sketchup and Ruby!

                          Fredo

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                          • fredo6F Offline
                            fredo6
                            last edited by

                            @roland joseph said:

                            I am saying for me at least generating a terrain with cloud point is not very exciting. It would be selfish to say I would rather a talent like you work on other things. 😄

                            I think that generation of terrain is an essential feature for Sketchup, not to say that making organic shapes from control points can be useful too.
                            Actually, this is not something simple to develop in Ruby, because of the lack of efficient algorithms and the variety of topological situation. So nothing straightforward in this plugin project.

                            Fredo

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                            • R Offline
                              roland joseph
                              last edited by

                              You are saying this one has you absorbed. If your motivation is the challenge then for sure I understand. Just one last curious question. Is this a personal effort or has it been brought on by pressure from others?

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                              • pbacotP Offline
                                pbacot
                                last edited by

                                Nice work Fredo! I think the generation of terrain is very important. I would offer some examples but I am not too connected on this end of things. Usually I am working from contours provided by others who have already developed them from points. I wouldn't know what the original data is like. You've made great contribution to this functionality in SketchUp that was pretty backwards just a short time ago, falling behind programs like Bonzai even. With ThomThom's, Tig's and ValiArchitect's tools, as well, things have changed radically for this sort of work. Thanks, Peter

                                MacOSX MojaveSketchUp Pro v19 Twilight v2 Thea v3 PowerCADD

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                                • JClementsJ Offline
                                  JClements
                                  last edited by

                                  Fredo,

                                  A fellow who works for my previous employer, Brown and Caldwell Environmental Engineers, suggested downloading 2006 LIDAR data for the state of Ohio here:

                                  http://gis3.oit.ohio.gov/geodatadownload/osip.aspx

                                  Hopefully, they aren't too big of datasets.

                                  John | Illustrator | Beaverton, Oregon

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                                  • fredo6F Offline
                                    fredo6
                                    last edited by

                                    @jclements said:

                                    Fredo,

                                    A fellow who works for my previous employer, Brown and Caldwell Environmental Engineers, suggested downloading 2006 LIDAR data for the state of Ohio here:

                                    http://gis3.oit.ohio.gov/geodatadownload/osip.aspx

                                    Hopefully, they aren't too big of datasets.

                                    John,

                                    Thanks. The link does not seem to work however.

                                    Anyway, the current prototype is not really adapted to LIDAR data in general, due to the density and volumes. I may come one of these days with something adpated to this cases.

                                    Fredo

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                                    • R Offline
                                      rodman100
                                      last edited by

                                      Here's some data to try out...a survey CAD drawing, both 3D and 2D, together with raw data (600 points, an interpolated 5m grid of the data and a visual of the terrain model as generated by the data.


                                      Survey Data.zip

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                                      • fredo6F Offline
                                        fredo6
                                        last edited by

                                        @rodman100

                                        Thanks very much, very interesting model. I imported from the dwg and had to eliminate an aberrant point.

                                        The results are in the attached SKP, based on different level of smoothing (best seems to be 25 deg.)
                                        Rodman100 - survey.skp

                                        Difficult for me however to say whether the terrain corresponds to the reality. Maybe you have some idea.

                                        Fredo

                                        Rodman100 - Survey - 25 -3.png

                                        Rodman100 - Survey.gif

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                                        • R Offline
                                          rodman100
                                          last edited by

                                          Terrain Model c.jpgThat looks good Fredo from the gif, I'm still on SU V14 so can't see your posted model but the surface looks similar to my terrain model, which from memory looked like the actual terrain. The contours can differ slightly when generated solely from points (as in my attached terrain model) as this method does not take breaklines (distinct interruption in the slope of a surface, such as a ridge, road, or stream)into account. But that depends very much on the particular site.

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                                          • pilouP Offline
                                            pilou
                                            last edited by

                                            You say cloud of points, but seems it's very similar of a cloth falling on volumes ?
                                            Maybe a cloth algorithm will be more speedy ?

                                            Frenchy Pilou
                                            Is beautiful that please without concept!
                                            My Little site :)

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