4 Replies Latest reply on May 26, 2010 11:07 PM by Dougal Hiscock

    Surfaces and point clouds from contours?

    Dougal Hiscock

      I'm trying to use solidworks to create a surface map.

      I've started with a 3D DXF/DWG (DXF seemed to import better) which gave me a lot of imported curves on different planes.  These have been converted to sketch curves on known planes and a boundary sketch using splines placed around the four corners (map boundary is rectangular).

       

      So far I've found a boundary surface using these four boundary sketches gives a good outline, but it seems to need countour lines in a completely different orientation to the contour lines I have.  Manually this would take a long time.

      I have scan to 3D, but it requires a point cloud or mesh file.  Is there an easy way to convert the contour lines I have to a point cloud so a surface can be more automatically generated?

      Is there a better approach?

       

      Also what is the maximum volume solidworks can handle?  I'm currently working with this at a 1/1000 scale (mm instead of m) as it initially tripped beyond the modelling limits due to the altitude in the contour map.  I'm hoping that once I have created the surface I can reduce the altitude and get it under the volume limit when scaled to full size.

        • Re: Surfaces and point clouds from contours?
          Charles Culp

          Dougal,

           

          You are not the first to try this. It was discussed here: https://forum.solidworks.com/message/20858#20858

           

          Read that thread, and then give us a follow up post if it helped.

           

           

          Also, the maximum size for a part file is 500 meters from the origin in any cardinal direction. So make sure you center your part around the origin if it is between 500 and 1000 meters.

            • Re: Surfaces and point clouds from contours?
              Dougal Hiscock

              Thank you for the link, I hadn't found that one in my searches.

               

              One of the approaches there (point cloud -> scanto3d) is what I would like to try.  But I need a method to convert a contour line map into a point cloud.

              I have the contour map in dwg/dxf and I have converted that to solidworks sketches on planes.

               

              The catch is I cannot export to a point cloud until I have a surface or solid, if I had a surface or a solid then I wouldn't need a point-cloud.

               

              Otherwise creating a guiding sketch every 100m (actually 100mm) looks like the best option.  It's just a lot more work.

              It looks like I will be outside the modelling limit (1300m x 1000m) so I'll see if I can split it when the surface is created then scale the individual parts.

                • Re: Surfaces and point clouds from contours?
                  Charles Culp

                  Well, I tried the "deform tool" just to see how it works. It works a bit better than I expected, but still no way to force it to actually meet the elevation lines. It approximates well, or meets the lines well. I have attached that example at the bottom of this post. When looking at it, you will want to adjust the "deform deviation". I have it set to 2.5 feet right now (halfway between each elevation layer). Try 15' to make it smooth (but inaccurate) or 1' to make it accurate, but stepped.

                   

                  As per your comments on Scan to 3D. No matter what you do, SolidWorks is not going to be able to interpolate between the contour lines very well. I'm not sure if any software will, but if there is one, it will be a mesh based modeler. The best mesh based modeler to use with SolidWorks is probably Rhino. It has a tool specifically to do what you are trying to do (sort of). http://www.rhino3d.com/  You can download a 30 day free trial, I suggest that. It can import DXF/DWG files directly.  With that, you can convert to a NURBS based model, which can be imported into SolidWorks. I am not really familiar with it, but it might be just what you need.

                   

                  Also, Part files are limited to ±500 meters, but assemblies are not. So if you are going to split it into chunks, no need to scale. Just assemble them in an assembly.

                    • Re: Surfaces and point clouds from contours?
                      Dougal Hiscock

                      Unfortunately I'm on SW2009 so I can't open your attached part file.  I've given you the four points anyway.

                      I have created a grid of splines over the countour lines in two directions at 100mm (100m) spacing and pierced every intersection.  This was a few hours work but has given me a usable surface.

                       

                      I am having problems scaling the split surface back up to size.  The chunk I'm working on is 600mmx995mmx100mm with the origin on the centre of the base, scaling it 1000x should provide distances from the origin of 300m, 497.5m & 100m.  But it spits the "outside modellng limit" error and I'm still looking for the source.

                       

                      I do have the rhino demo.  But I'm obviously trained into the solidworks mindset because I can't get my head around using it.  I know a rhino guru but I think he's on holiday.