13 Replies Latest reply on Jan 20, 2017 3:30 PM by Bruce Lane

    Model Land Topography

    Bruce Cox
      I'm trying to model land topography. I traced a topo map image onto surfaces spaced at 10' elevations. I extruded the elevations into a solid for a visual but would prefer a single smooth surface. Any suggestions?

      I was hoping to make 4 outside edge sketches by connecting the dots... then use a "filled surface" from the 4 sides... and use the traced elevation sketches for constraint curves. No luck, I can't even get a filled surface to span the 4 outside edges.

      The next ideal (bottom picture) was to dice up the elevations into a bunch of sketches and try a loft. The way I'm doing it will probably take 4 hours with no guarantee of success... so I thought I'd stop and ask the experts.
        • Model Land Topography
          Charles Culp
          My first thought would be to create a "starting and ending curve" that ran from the top of the mountain to the bottom of the valley. then use a boundary surface/surface loft with the elevation lines as the "guide curves". Note that you may not be able to do the very top peak/bottom valley. So just do between the lines, then fill the peak with a filled surface and "tangent to edge" constraint.

          I noticed you have a few "mini valleys" which would have to be separate boundary surfaces.

          If you post a .zip'd .sldprt file I might be able to take a look at it at the end of the day today.
            • Model Land Topography
              Bruce Cox
              I should have played with a small area first.

              I think lofting between elevations could work if I smooth out the splines... made sure they didn't make an "S" bend, and added a few guides. Humm... maybe split the splines to force the faces to behave.

              Do the number of spline control points have any influence on Lofts? Is lofting between a spline with 3 control points and a spline with 4 control points... the same as lofting between sketches of 3 segments and 4 segments?

              That 2nd pic... slicing up the elevations and drawing "connect the dots" sketches to make loft guides worked... sort-of. The surface was noticeably "griddish".

              I mostly wondered if there was a usual technique to do terrain. I'm sure I'm not the first to model his backyard.
                • Model Land Topography
                  Gary Garrison

                  Bruce Cox wrote:

                   

                  I should have played with a small area first.

                  This really sounds like something I would do. I am trying to model an eagle like on the Eagle Scout rank badge. The problematic area think will be the feathers which are visible on the ribbon badge with the pewter eagle hanging from it.

                   

                  I mostly wondered if there was a usual technique to do terrain. I'm sure I'm not the first to model his backyard.

                  Could the deform tools do this? Or are they not accurate enough? I haven't used them myself. Maybe a fillet/chamfer on the edges?

              • Model Land Topography
                Bruce,

                Have you tried the Deform feature using the custom shape option? Deform allows you to deform a body using another body as a deform tool with a tolerance offset to get a single smooth face.

                Its computationally expensive, but you might get it to work with the right offset values and position. In the topo model you've created, create a new body (and don't merge it) over the current topo solid. then experiment with the deform feature.

                In experimenting, I'd use only a small portion of your topo body (insert a cut feature)
                • Model Land Topography
                  Charles Culp
                  I have been looking into this, and will retract my earlier comments about using boundary surface. I think some of the other tools mentioned might work better, and boundary probably won't work at all.

                  I did want to mention that 3DS Max has a cool feature where you can use a bitmap image (Grayscale) to create a deformed surface. The brighter the white the higher the elevation. That gets used quite a bit for terrain mapping. I know that's how they did the terrains for Myst and Riven (although they used Lightwave). I have used it successfully to map some land. It is, ofcourse, mesh modeling (and owned by the competition!), not NURBS like Solidworks.

                  Also, I have an idea, but I figured you already had the "stepped" model. Try using the "indent" tool, with a very large draft angle. Use a flat surface, with the "stepped model" as your indent tool. Maybe you can get something that looks good using that.
                  • Model Land Topography
                    Kevin Quigley
                    That's a very complex surface you have there, not helped by the plan shape of the bounding edges (not rectangular). You are getting areas where the equation "yes Solidworks can do it vs but it takes a tenth of the time on something else" comes into play.

                    It you want a polygonal surface for rendering etc, download SketchUp and use the site modelling tools in that - it takes 5 mins max. You could then export this back into SolidWorks if you have Premium and use Scan to 3D to help surface it. Alternatively download the Rhino demo and model it in that - maybe 10 mins (you get 25 saves with the demo BTW).

                    They if you are really feeling brave download the VectorWorks 2009 demo and create a site model from the contours, save as a parasolid file and import that into Solidworks - 5 mins.

                    In Solidworks itself from scratch I'd run with the deform or freeform features and do it by eye. Overlay a block or new surface over your stepped model and use those tools to push and pull until your contours are just visible.
                      • Model Land Topography
                        Bruce Cox
                        Thanks for the suggestions. I didn't try Push yet. I did try Boundry Boss and when it started failing at the same elevations as a loft. I decided it was combining a loft and extrude to surface. (right?) Although if I broke it up into smaller pieces it might have worked. I downloaded Sketchup a few weeks ago to import some of their library models into SW... but I found no way to export that SW could import.

                        So I concentrated on lofting one elevation at a time. Not the picture perfect result I was looking for, I made straight guide rails instead of smooth splines so it's edgy. But the straight lofts were problems enough. You can see I had to hem the bottom of the gullies together, the lofts wouldn't make the tight turns without degrading. Imagine my joy when it finally knitted together. The finished model is 2000 foot x 1760 foot. Where I started the origin I actually ran out of model space on one side.

                        So the next question... how to model 3000 trees?
                          • Model Land Topography
                            Pete Yodis
                            Bruce,

                            Interesting post. I have this exact need. I am starting with a DWG file of a survey of a plot plan with countours and elevations. I would also like to see it as a 3D surface. (This could be cool with flow simulation for water-run off). I have messed around for a few minutes, but nothing serious yet. I'll take into condsideration what I have read and seen here.

                            Pete
                              • Model Land Topography
                                oliver leyland
                                I've been working on creating a solid, smooth landmass recently and have got really good results using the scan to 3d add in and equally good results using a free surfacing program to create the surface and Soldworks to do the rest. All you need are a set of .xyz coordinates for your landmass and a lot of time and patience.

                                If you have scan to 3d and you are able to obtain a set of xyz coordinates for the area of land you are working on in either a .xyz format or a .txt format you can open them up in Solidworks to create a point cloud and then using the mesh wizard a surface. Depending on how complex the surface is you can thicken or extrude it. If this does not work create a sketch on a plane below the surface and project the edge of the surface onto it. Then extrude up to surface. Hide the surface and you are left with a solid landmass.

                                If you do not have the scan to 3d add in there is a free program called Point Cloud 1.0. This can be used to import your xyz coordinates and create a smooth surface. There are several different formats you can save your surface as and from what I can remember some didn't open in Solidworks but I think .SAT and/or .DGN worked. This gave me an imported surface in Solidworks. I then used the extrude up to surface method described above and it worked a treat.

                                I am now able to cut the landmass up, cut into it for foundations etc. The landmass in the attached image was created by importing xyz coordinates provided by a survey company into Point Cloud 1.0 to create a surface. As decribed above I then imported the surface into solidworks to create the solid mass.

                                Its a pretty big area 1.5 hectares or so and with buildings and stuff modelled in I think it was starting to push the boundaries a bit and the whole assembly started to slow up. I recently upgraded to a 64bit system with 8 megs of RAM and it runs much better.
                          • Re: Model Land Topography
                            Bruce Lane

                            1. Create XYZ tables of points in approximate lines. (note: just do not cross lines.)
                            2. Create curves with "Curve Through XYZ Points" tool.
                            3. Use "Boundary-Surface" to create your surface with the curves by adding them to the direction 1 list.


                            This should give you a shaped surface that approximates your land shape. The more points you use and the more Curves you use the closer to the actual it will be.  Below is an example table as a delimited text file. The first is E/W the second is Height and the third is S/N looking down from the top. 


                            -1.00m 16.00m -1.00m
                            -1.00m 16.30m 2.05m
                            -1.10m 15.80m 5.00m
                            -1.00m 15.60m 8.10m
                            -1.05m 15.20m 11.00m
                            -1.00m 14.30m 14.00m
                            -1.00m 13.60m 17.05m
                            -1.20m 12.80m 20.00m
                            -0.90m 11.40m 23.10m
                            -1.05m 10.20m 26.00m
                            -1.00m 9.00m 27.00m
                            -1.00m 8.30m 30.05m
                            -1.10m 7.20m 33.00m
                            -1.00m 5.40m 36.10m
                            -1.05m 3.20m 39.00m
                            -1.00m 0.40m 42.10m
                            -1.05m 0.10m 45.00m

                             

                            Notice this example is in meters, SolidWorks will convert to inches for you.

                            • Re: Model Land Topography
                              Bruce Lane

                              See Attached Part File