8 Replies Latest reply on Jun 20, 2007 4:11 PM by 1-59EXF5

    Surfacing using 3d imported curves?

      I have an iges that was imported from some CMMsoftware. Its contains a curve representing the measuredsurface.

       

      We need a reasonably accurate model of thepart (its sheet metal) but it's much too complicated to measure andmodel.

       

      Is it possible to create surfaces from thesecurves?

       

      Im not veryfamiliar with surfacing so any input or direction isappreciated.
        • Surfacing using 3d imported curves?
          Charles Culp
          You've hit a very sticky part of Solidworks, which is that curvesand sketches do not behave the same way.  I suggest making a3D sketch and using the "convert entities" tool to createboundaries for each section of the part you want to surface. Then make a lofted surface to cover that area.  You maythen want to go in and touch up some of the areas that have a moredefined shape with regular extrusions/etc.

          It will probably take a long time to get all the surfaces to matchup, and to knit them together (which can then forms a solid). I would estimate it would take me 3 hours for theinitial lofts, then double that time to make it all clean, andmatch the desired end product.
          • Surfacing using 3d imported curves?
            David Davis
            Hi James,

            Nothing is to complicated to measure and model Everything just poses a new set of challenges, which can grow your arsenal of mental tools.

            It looks like you are trying to measure / model a Rear Fender for a motorcycle application, which is something I've had to do in the past. So I've got some suggestions and examples for you, that may help. For reference, it would probably take me an hour on the PCMM, and maybe 1-2 hours to model the part up in CAD.

            When using a FARO arm (or any PCMM/CMM) it's important to establish a coordinate system on the part you are measuring. This allows the transition from *.IGES file into Solidworks to be more robust. This way you can use as much FARO data as possible. Even if it looks like the part doesn't have a coordinate system. This is done with the "Alignment" or similar feature, the most flexible is the 3-2-1 method which is similar between a lot of softwares/hardwares. The most important part here, is Establish an Alignment

            If the part is meant to be symmetrical, then try to establish the origin in the centroid of the part. This will help with every part. You may have to mark the part in order to guide yourself in creating features. My most important things I have is a Black Permanent/Laundry Marker(for light colored parts) and my bottle of Liquid Paper (for Dark colored parts) so I can consistently measure the same feature that is projected onto different planes. This is so you can establish axis and circle features across the part

            For the Fender you are working on, I'd use these steps to measure/model the part in question. Please have a look at the Fender Scan_ Front.jpg and Fender Scan_ Iso.jpg for a visual reference.

            1. Measure a plane on both of the "Sides" of the part.
            2. Mark a proposed Midplane circle on the outside of a part (with a permanent marker or similar) on the greatest diameter of the Fender
            3. Measure this circle (OD Circle) on both sides of the part, total of 2 circles measured.
            4. Create a "best fit" line in between these two circles (Make sure there is no plane selected when creating the Best Fit line)
            5. Create a Midpoint between the two circles you've measured.
            6. Create a Plane, Perpendicular to the Line at this Midpoint Feature (Much like you would in Solidworks, we are now starting to get some similarities between the RE Software and the CAD software).
            7. Measure enough features, to create a direction. This means 2 Circles, 2 Points, or 1 line. You need a reference to start from, and a direction to point to for the Alignment. A line is the simplest, but often hard to measure on a part that doesn't have a straight edge.
            8. Now do the 3-2-1 Alignment. Your Plane is the Perpendicular Plane (step 6) you created. Your Origion is the Midpoint you measured. Your direction is the features you measured in step 7.

            Now you have a coordinate system for your part. More importantly, you have all the planes and reference geometry that comes with it! Now you can sketch on that Midplane, at the symmetry plane for the part. Very important.

            Now just measure enough features to bring back into Solidworks/CAD. Use those XY/XZ/YZ Planes to your advantage, because they will come directly into Solidworks, and show up in the Front/Right/Top planes. It makes working with this PCMM/CMM data easier, and more correct. I cannot stress enough, how important it is to Align the PCMM/CMM to a coordinate system on the part.

            A very good tool is the Scan feature for a FARO arm software. This allows you to do contours, instead of doing the 3D Freehand Scan. An important note : remember to offset the resulting features 1/2 of the Ball Probe diameter!

            I've probably gone on too far, but it's important to use all the tools available that will help you in your job or whatever you are working on. Good luck,
              • Surfacing using 3d imported curves?
                Anna Wood
                David,

                Thank you very much for your very infomative post. It is this sharing of knowledge by the users such as yourself here that make this forum great.

                Kudos to you....

                Regards,
                  • Surfacing using 3d imported curves?

                    I thank very much for the informative post aswell. I understand the reason to build the alignment and how muchit helps. My biggest struggle was working with what data I had insolidworks. I do not have much (nearly none) experience in complexcomponents such as the fender and fuel tank in your images.Unfortunately I was not given adequate time to work out thisproblem as much as I would have liked.

                    The method I stumbled upon involved building apoint cloud of the product, then using solidworks scan to 3d wizardto build a surface. This was close enough for now. But in thefuture I may be required to build something more accurate.

                    Again thankyou very much for your response. As Anna stated it is user like youthat really make this forum work!
                      • Surfacing using 3d imported curves?
                        David Davis
                        Hi All,

                        I appriciate the praise. I'm glad to help in any way that I can, if it's something I have knowledge of.

                        James : What size (diameter) ball probe was used with the FARO/Romer arm? I may be able to model up your part somewhat properly today, since I have a small break in my schedule. That way you (and everyone) can see an example in SW, since I cannot release document controlled models from work. But I can definetly show the logical progression in a feature tree of a SW model.

                        Just let me know

                        Thank you,
                          • Surfacing using 3d imported curves?
                            Iused a 3mm Probe. The file was created using a freehand scan. Couldthat information be used to create something? It seems whatever Itry to do with it my machine just gets completely boggeddown
                              • Surfacing using 3d imported curves?
                                David Davis
                                Hi James,

                                I've got the file ready. It just has the exterior surface with a trim, then thickened.

                                It should help show how to take an overwhelming amount of data, and get the important parts out of it. I'll still stress that you must Construct->Alignement->3-2-1, as it will only help out. Plus you'll be able to communicate better with QA/QC when it comes time to check first articles

                                You'll want to make sure that the model is parametric, so you can make changes for the Design department. This will help relieve future headaches.

                                Please feel free to ask questions, I enjoy dealing with using PCMM's into Solidworks without using difficult interfaces and the like. The most important thing is to understand how you affect the Solidworks model with what you do in the FARO software.

                                Hope this helps.
                                  • Surfacing using 3d imported curves?

                                    That looks good, Thank you for taking the timeto do that.

                                    I see and understand the method youused.  I understand the point of an alignment, for thatexample though I skipped it just to get some quick data to playwith in Solidworks.

                                    If I get somefree time I will try to replicate your results.