31 Replies Latest reply on Nov 9, 2018 9:58 AM by X. Liu

    XNurbs - further investigations

    Kevin Quigley

      Following on fron the original Xnurbs thread - I thought I was perhaps being a bit unfair in not properly reviewing what this offers. The other thread got a bit out of hand so I decided to install it (on SolidWorks 2018 SP0.1) and run it through a couple of typical types of jobs we do -and where we have had issues with SolidWorks own surfacing commands.

      One of the problems with the way the XNurbs guys presented the other thread was to show it as a glorified Fill Surface tool working on complex patches. This has merits in many situations (I mean, who here has never used Fill to get them out of a hole occasionally). But as a product designer I knew that this is a kind of irrelevent example for design phase surfacing. We always set up curves - the curves define the form.

      So I set up a form based on a medical product we are working on right now, and did a comparison.

      xnurbs1.JPG

       

      So excuse the snipping tool mouse text, but the above is typical of a set up - curves (always splines not lines and arcs), define the form, helper surfaces at the centre line (this form is symmetrical) and at the split line - taking off at 2 degrees draft.

      So the above shows the X nurbs surface - which was very easy to pick and select the edges of surfaces and curves. There are actually two Xnurbs in this - the main surface and the front capping surface.

       

      The next one below shows the SolidWorks Boundary Surface - with exactly the same inputs. I have sectioned the part to show the differences, and mirrored the Xnurb surface for clarity.

       

      surfae1.JPG

      Straight away you see the issue with the SolidWorks Boundary Surface tool - this is very typical of this tool - you can see clearly that the surface created is not at all right and it creates a huge undercut - this despite setting up helper draft take off surfaces. In short, it does not follow my "design intent". In the past we have had to add more intermediary sketches to define the form (same with a loft) but this generates ripples and lumps and bumps. I also did a Loft surface for comparison and tried a few different variations but this created some nasty ripples and the same generic form as boundary with the big undercut.

       

      Next I tried SolidWorks Fill Surface. The Fill Surface uses technology taken from CATIA, so gives a slightly different variant of the form.

      fill surface.JPG

       

      Not bad but you get this lump at the front, which would be unacceptable. In the past using Fill for these types of surfaces has caused this kind of issue - you think it is OK but when you do a deep dive taking sections and using environmental reflection analysis the flaws pop up.

       

      Only by deep diving into a surface can you actually see the issues. For comparison here are all 4 versions on a section.

      section.JPG

       

      In this context, wioth these inputs, only the Xnurbs and Fill are following the design intent. The others generate undercutting surfaces.

       

      Finally I imported the Boundary, Fill and XNurbs into SharkFX software - where I can display the surface CVs and create interactive surface ISOs. FYI Shark FX is pretty good.

       

      comparison.JPG

      Here you can clearly see the differences between the surfaces and the way they are generated. Boundary is created to the edges, and that is the edge of the underlying surface, so the CVs and ISOs all follow these curves - so this will give you the best "flow". As a boundary surface goes this one is not actually too bad in terms of numbers of CVs. Most that we do have a LOT more than this. But note the bunching at the front. These areas can lead to issues further downstream.

      The Fill and the XNurbs are both trimmed NURBs surfaces - so you take a 4 sided Nurbs (all NURBS are 4 sided) and trim the form to fit the boundary edges. You can see that the XNurbs underlying surface has a bit more "space" than the Fill surface version - though the Fill surface is less twisted (rlative to the inputs). But note that lump at the front of the Fill.

       

      So in summary, I think XNurbs is actually pretty good! I cannot say if it is the "best NURBS tool ever", but I can say that compared to the existing toolset in the latest version of SolidWorks it offers something worth having. One final point.

       

      I mentioned issues with CVs bunching leading to downstream issues. This dhows itself particularly in operations like shelling, where the software has to create an offset surface, trim it, then stitch it all into a solid (all happening under the hood). Look at those surfaces above - the untrimmed versions. The XNurbs surface is the least bunched so you have a better chance of offsetting and shelling.

       

      What I did was finish the component off - mirrored the surfaces, created XNurbs for the back and base (rather than planar - which for some reason did not take), stitched it all up then shelled. I then made some tweaks to the curves to see how robust the XNurbs construction was. We all know that SOlidWorks in built tools are generally OK but can lose associativity occasionally, but XNurbs seems fine.

      shell1.JPG  shell2.JPG

       

       

      So in summary, I think XNurbs has promise. In terms of improving it if there was a way to force the surface created to flow along a particular vector that would be good, but as a v1 it is a very nice add on - quick, robust and surpasses many of the in built SolidWorks tools.

       

      I like it.

       

      But please xNurbs - stop using those daft n sided patches as examples files!!

        • Re: XNurbs - further investigations
          Chris Dordoni

          Thanks for that, yeah the prev thread got a bit clouded. I often struggle with having the minimum number of curves to define a surface without the ballooning or kinking and at the same time have enough control to ensure the surface goes where I want it to.

          • Re: XNurbs - further investigations
            X. Liu

            Kevin,

             

            Many thanks for your work.

             

            For your example, XNurbs should generate a better result (better surface quality and less control points) if you try the options shown in the image below.

            XNurbsOptions.png

             

            “please xNurbs - stop using those daft n sided patches as examples files!!”

            These examples are good for one thing - NURBS software developers will give up any attempt to challenge us even we claim “the best NURBS software ever”, but they may turn off experienced end-users. Yes, we do need to use other examples for users.

             

            Could you advise us that, comparing the following two examples (Network of Curves and Y Lofting), which one is better from the viewpoint of experienced users? Both are bad examples?

             

            “Y Lofting” XNurbs surface

            Y Lofting.png

             

            “Network of Curves” XNurbs surface

            Network of Curves1.png

             

            "there was a way to force the surface created to flow along a particular vector that would be good"

            Yes, this can be done within a week: just disable some optimization process inside XNurbs for 4 sided boundaries, which should generate a better result for your design. In other words, the edge of the underlying NURBS surface is the curves/constraints specified, so the CVs and ISOs all follow these curves.

              • Re: XNurbs - further investigations
                Kevin Quigley

                Thanks Kevin (this could get confusing )

                I'll be using this on another job today and tomorrow so will experiment with the two settings you describe, thanks. Unfortunately, as SolidWorks does not allow the display of surface CVs or ISOs I need to export to Shark or Rhino to see them - so SolidWorks, how about enabling this very basic functionality eh? If a minnow like Shark, Ashlar, Rhino etc can do this why not you? Sorry I digress.

                 

                In terms of example data, the n sided patch and the Y branch are good for users who tend to stay in the Solid modelling sphere only, and it does show what the applicaton can do, but, as I think you found on the other thread, and certainly in the Rhino forum, experienced users tend not to work like that. That network of curves is more what we would tend to do but that is probably overly complex (though if it can do that, and retain the associativity then great). I tend to try to build in robust editing into a model, as they ALWAYS need tweaking after it is shown to a customer (just move that a bit/show me some options where that is more curved etc etc). This is why for the concept phases that example I showed would be all that is needed. There is a balance to be had between boundary and internal controls. I tend to use internal controls to define localised forms, and in truth have one big surface may not actually be the best solution. We tend to work with - boundary curves, a few internals, big surfaces, then tweak curves to get the shape needed, then add localised detail by cutting trimming and patching in the new detail form (like a surface indent). That way, your big surfaces are generally quite robust to editing, and any downstream issues with details are more easily solved.

                 

                I think I get what you say about the CVs and ISOs. I wouldn't be so concerned about using the edge as the boundary (as in the SolidWorks Boundary surface approach). Rather, the bigger xNurbs/Fill trimmed to size is likely to be more robust downstream, so perhaps just a way to define a vector (or curve) to start the ISOs flowing along. The SolidWorks Fill kind of does this, depending on where you select first. Obviously though, if you can add a "boundary as ISO flow direction) option that lets users access what they want. At the end of the day, the more options you give users (in an interface that is easy to access) the more likely they will use the tool.

                  • Re: XNurbs - further investigations
                    Mark Biasotti

                    Fill, in it's non-optimized option, as you can tell from the preview lays an arbitrary UV direction over its boundary patch; this is what makes it work so well over boundary and other coon patch procedures that derive their UV direction from the surrounding surfaces (and then become problematic when adjacent surface patch directions are in conflict).

                    Maybe I'll ping my friend and former colleague Xavier Benveniste who is a programmer/mathematician that brought the Fill feature to SW from Dassault and has improved on it in both in SW and 3Dx. I'd love to hear his explanation for Fill and for the Boundary issues Kevin presents (oh yeah - he also did Boundary) but not sure how comfortable he would be sharing. Actually it is really selfish of me because I miss just walking over and asking my colleagues anything and they all are so talented and always gave me very good explanations.

                     

                    Mark

                      • Re: XNurbs - further investigations
                        X. Liu

                        Mark,

                         

                        For years, SolidWorks supports our plugin R&D. Do you think Dassault R&D teams were unaware our progress? FYI, SolidWorks also installs our plugin …

                         

                        If I were you, I would remove your former colleague name from your post. (If I would mention my former colleagues’ names and ask them to compete with the tech, it would upset and embarrass them.) You might corner your former colleague unintentionally.

                      • Re: XNurbs - further investigations
                        X. Liu

                        Kevin,

                         

                        Thanks for your explanation. Now, we better understand end users.

                         

                        For other NURBS software, the "Network of Curves" example may be overly complex, but for XNurbs, it is just an ordinary case and XNurbs has no problem to handle it. (The instruction of "Tips" in XNurbsHelp.chm contains the details that should address most issues for using XNurbs).

                         

                        The other Kevin

                    • Re: XNurbs - further investigations
                      Mark Biasotti

                      Hi Kevin,

                       

                      Thanks for the review.  In Boundary, does not the optional mesh preview help you with visualizing the UV's of the previewed Boundary surface? 

                      Also, would adding a connector in Boundary help you with your design intent?  And, did you try to play with the 1st and 2nd direction options which are by default set to global. I often times find that "next Curve" will help the Boundary surface to flow better depending on your boundary conditions (i.e. contact or tangent etc.)

                       

                      Would it be possible to post your model?

                       

                      Mark

                        • Re: XNurbs - further investigations
                          Kevin Quigley

                          Hi Mark, I will try and post the file later today. In terms of boundary tool options, yes we would usually play around with these to optimise the surface but tend to find that the preview  Fails to pick up some wrinkles. Also, the more connectors you add, the denser the surface becomes (usually). In this particular case I was interested in testing the immediate results using these tools and (importantl) the robustness of these surfaces to edits and downstream operations.

                          Now if SolidWorks allowed interactive iso and CV display and editing....

                        • Re: XNurbs - further investigations
                          John Layne

                          Thanks for sharing, could you share your original models? I'm on 2017 SP5 so they might not be any use to me but, I'm keen to see what Mark could do with the original data, using standard tools.

                          • Re: XNurbs - further investigations
                            Brian Brazeau

                            I'm glad to see the demeanor of these posts being a little more receptive to XNurbs. I'm not affiliated to them in any way, but I did think the other thread began to revert into a less informational and more XNurb bashing session. (You can't fault X. Liu for touting XNurbs as "best NURBS tool ever" it is his baby! Haven't you ever heard of "Best cup of coffee ever"?) This post will probably hurt my popularity with some of the posters of that original thread, but I always speak my mind. From what I'm reading, it seems XNurbs is beginning to show merit. Kudo's to X. Liu for his perseverance and temperance. I look forward to further posts in this thread to interrogate XNurbs more closely. Ultimately, it is the SW user who benefits from this discussion because we may have a piece of software that brings SW surfacing to the next level. Hopefully, more examples will be incorporated and any issues or advantages in XNurbs will be brought to light.(wasn't there an associativity issue mentioned in the last thread?)

                            • Re: XNurbs - further investigations
                              Kevin Quigley

                              I'll add a few follow up points discovered yesterday, and answer Mark's points about Boundary...

                              I have also added the file that contains all this.

                               

                              OK - first up - Mark.

                              Yes, I tend to play around with all the settings in Boundary as and when, but they tend to either not do anythign worthwhile, or create even worse issues. On this particular case I was focussed on comparing the surfaces created with a limited input set to see how xNurbs compared to the existing toolset. In the screenshot below you can see another boundary surface with two added connectors:boundary options.JPG

                              On this particular form (which I chose for a reason, as I have previously had to work on this shape and it caused issues then) the boundary does not allow you to create a form without an undercut, using curvature constraints on the top and bottom surface edges makes this issue even worse. Yes you can play around with the magnitude of the tangency influence but this tends to generate creases or less rounded forms:

                              boundary options2.JPG

                               

                              The iso preview on Boundary is helpful but once the command is done the iso display goes. Why can't SolidWorks not simply allow the user to display the surface iso? Never understood this. If SolidWorks also allowed the display and selection and editing of surface CVs this would alleviate a lot of the issues we face. Again, no technical reason why they can't do this. Sorry I digress.

                               

                              Commenting on the other items in the thread and the model Paul did, yes, I agree, you can add more intermediary curves aor break up the main boundary into smaller ones, but in my experience this leads to a less robust model for editing. But yes, that is exactly how I would normally do this form. But what I was focussing on here was seeing how xNurbs handled my specific case with a limited number of inputs.

                               

                              Finally, the xNurbs surface generated on this model is (in my opinion) the best of the bunch, but it does not fully meet the design intent. If you examing the nose of the shape you can see that the surface tends to dip in slightly:

                              Dip Xnurbs.JPG

                               

                              This is not that surprising but I really wanted the surface to constanting rise from the nose, not dip then rise. I tried adding an internal control point but this made no difference at all, even when playing with the quality settings in xNurbs and Image Display (I thought it was a display issue at first but this screenshot has the display setting cranked up to max)added point.JPG

                               

                              Anyway, its Friday, I've been on the road for 4 hrs today, time for downtime

                                • Re: XNurbs - further investigations
                                  X. Liu

                                  Kevin,

                                   

                                  Using internal curve constraints should meet your design intent (For your example, an internal point constraint has very limited influence). For XNurbs, adding internal curve constraints won't cause the generated surface to become denser. In other words, adding internal curve constraints has no impact to the number of NURBS control points generated. So you can add a network of internal curves without the side effect. (The internal constraints do not need to be precise, as they work like an “attractor” and “attract” the surface to the desired position.)

                                   

                                  The following image comes from the "Tips" in XNurbsHelp.chm, which explain the details of using internal constraints ("Boundary VS. Internal constraints").

                                  Internal Curves.png

                                  The other Kevin

                                • Re: XNurbs - further investigations
                                  X. Liu

                                  We took a quick look at your model with xNURBS V2. The following shows the quad-sided result from V2 (with the same input as your model). (V2 has an option to generate quad-sided, i.e., un-trimmed, or trimmed surfaces. In other world, you can somehow control UV flows.) Also you can use other options to further tune the results. Compared with V1, with the same input, V2 should generate a better result.

                                   

                                  Untrimmed.png

                                   

                                  Sorry for the delay of V2 release. We have been waiting SolidWorks’s approval to release V2 for a while. While SolidWorks seems to be very happy with our product, it looks like that, for our application, SolidWorks needs to get some approval/agreement from its parent company and they have been discussing our application for quite a while. SolidWorks said ‘they are working very hard’ to process our application. We believe SolidWorks, so we rescheduled our release plan.

                                   

                                  Apologize for the V2 delay. Hope SolidWorks can sort it out very soon.

                                    • Re: XNurbs - further investigations
                                      Kevin Quigley

                                      Looks good! We have used XNurbs on a few production projects now and it has proved invaluable both for quick design phase surfacing for concepts and final prodiction surfacing. So far it has been very robust so I can't see why SolidWorks would delay approval. Now I just need to figure out how to move the license to a new workstation!

                                        • Re: XNurbs - further investigations
                                          X. Liu

                                          From the very beginning of our application, SolidWorks told us clearly that they have no problem to approval our application.

                                           

                                          I guess the delay might be caused by the nature of xNURBS capacities – maybe it is a bit over-powerful. SolidWorks and Dassault are fully aware xNURBS’s capacities and the kernel powering xNURBS... What I don't understand is: SolidWorks has been helping us to develop the addin for years and this gives its R&D teams a chance to watch our progress closely. So they should be able to approval our application quickly, but instead, now they need very long time to discuss it.

                                           

                                          I believe SolidWorks is a respectful company, so we delay our products' release to give them more time.

                                           

                                          “Now I just need to figure out how to move the license to a new workstation!”

                                          We already scheduled to release a minor update (V2.01) to address the license transfer issue after the release of V2. If you need to do it now, we can directly manipulate our license server to do that.

                                            • Re: XNurbs - further investigations
                                              Kevin Quigley

                                              No rush on the transfer - I can wait - we have the other license on another workstation anyway.

                                               

                                              As for the approval process, well I filled in their forms months ago. I can't see that adding functionality to the application would affect approvals - add ons like Power Surfacing introduce sub d workflows that CATIA uses for some very expensive modules (Imagine and Shape). More likely it is to do with them preparing for the forthcoming product launch of SolidWorks 2019.

                                                • Re: XNurbs - further investigations
                                                  X. Liu

                                                  Kevin,

                                                   

                                                  Thank you very much for your help!

                                                   

                                                  SolidWorks installed xNURBS at the very beginning, before your evaluation.

                                                   

                                                  To my knowledge, on July 9th, our application might not be controlled by SolidWorks, and others got involved... Hope SolidWorks can understand we have been waiting a very long time.

                                                   

                                                  Since Dassault knew all details about our history, so we post it on our website: xnurbs.com . The only thing that you don't know is I am a former employee of PTC.

                                                   

                                                  You are right that adding functionality to the application would not affect approvals. I am afraid that the delay is caused by our xn kernel not xNURBS addin. The kernel is based on variational surfacing technique, which may provide the ultimate solution for NURBS surfacing.

                                            • Re: XNurbs - further investigations
                                              Mark Landsaat

                                              The increased options for V2 are interesting. I downloaded the trial for V1 and found it to be an alternative to the SolidWorks fill feature. Yes it creates nice results in N-Sided holes, but SolidWorks Fill is actually pretty good as well. I try to avoid 5-sided surfaces, and If I do use them I try to set them up so they have a somewhat evenly distributed polygonal shape. In these cases the fill feature typically will give me an acceptable result. Better surfacing features are always welcome since SWX doesn't do any development in this regard.

                                               

                                              It sounds like you have a very strong background, can you add NX like functionality to your XNURBS plug-in? NX runs on the same Parasolid kernel as SolidWorks so clearly the geometry kernel has much better surfacing capabilities than what we have with SWX features. I have and love GeometryWorks 3D, Blend Curves, Blend Surfaces, Conic Surfaces, Pipe surface, Fence Surface. Those features really extend SWX (in my opinion) Things we don't have that exist in explicit modelers like Rhino and Alias.

                                               

                                              "Rebuild Surface". Rebuilding a surface to a desired degree and number of control points for UV direction. Great for building primary or slab surfaces. Also really good for cleaning up geometry. SWX often times creates incredibly dense UV surface patches with a wobbly rippled surface. Rebuilding a surface can often remedy this. Use this a lot in Rhino.

                                              "Match Surface" a match surface command with G0, G1 and G2 options. G0 with the option to not refine the surface. This is great when building to a theoretical edge that you are going to blend out later. Keep the primary surfaces single span even if this leaves a small gap. If you're building to a theoretical edge this will get trimmed out and filled with a blend surface at a later stage.

                                              "Surface Pullback" in the same category as the match surface. When two primary surfaces are build single span trimming them back will often increase edge complexity for no reason. both Alias and Rhino have an edge pull back where the edge will follow the control points and redistribute to move the edge along the surface. Yes this causes a small deviation in the surface, but if the surface quality is single span pulling back surface edges will allow the secondary blend surfaces to respect the clean input edges and often times the result can be kept single span this way.

                                               

                                              Any geometry creation tools that create clean 4-sided surfaces. I currently use native SWX loft/boundary/fill, and Push-Pull/Multi Blend and Conic Surface from GW3D. All these features will create different geometry with the same input. In most cases one of these six will create a good result, but not in all cases. Admitted in the rare case it does not, most of the time the input geometry isn't very good, but sometimes we have to close up a volume in a way that is less than ideal and we need good results. I'm wasting way too much time trying different features to get the results I want.

                                               

                                              Anyway, sort of rambling. But the gist of it is this. If you add good surface creation tools to XNURBS with a good user interface that gives us control over the end result, I will be a customer for sure.

                                                • Re: XNurbs - further investigations
                                                  X. Liu

                                                  Mark,

                                                   

                                                  It is very easy to show that xNURBS is NOT an alternative to the SolidWorks fill feature. For example, in the example below, select the 5 edges (specifying G2 continuity, marked in the image), xNURBS will create a lofting/blending/filleting surface.

                                                  Lofting.png

                                                  How about the example below? What could you call it?

                                                  Y Lofting.png

                                                  As Kevin Quigley said, “it has proved invaluable both for quick design phase surfacing for concepts and final production surfacing.”. I don’t think it means "fill". One of our users is a well-known American bicycle manufacturer (in your field!). xNURBS is “one for all” – one simple UI for all kinds of applications! The truth is that, except for very special cases, i.e., analytical surfaces, xNURBS is superior than traditional surfacing methods, i.e., it produces better results!

                                                   

                                                  We are a bit confused by your comments: It means that a better document is needed to show how to use xNURBS, but xNURBS is very easy to use and our users do not have any problem with it. (The only issue our users complained is ‘license transfer” – users want that each copy can be used on multiple computers, just like SolidWorks.)

                                                   

                                                  Thank you.

                                                    • Re: XNurbs - further investigations
                                                      Mark Landsaat

                                                      Hi Mr. Liu,

                                                       

                                                      Totally agree with you that the above cases are not the fill feature. and I stated in my other reply that this is interesting. You have received quite a bit of feedback from very experienced SolidWorks users on possible ways to improve the user interface. I'm not disputing that your XNURBs plugin doesn't create nice geometry, but I believe the plugin could benefit from more buttons for specific operations.

                                                       

                                                      All SolidWorks geometry is created by the Parasolid Kernel, but we don't have 1 button for geometry creation. For users this is split up into a lot of different operations. We have a button to extrude geometry, to revolve geometry, to sweep geometry etc. etc.

                                                       

                                                      The above images are actually a very good illustration of my point. The 4-sided surface from Kevin is a totally different action/operation than the 3 separate surfaces with reference geometry. It is my opinion that it would be beneficial for your plug-in to have separate buttons and names for these operations.

                                                       

                                                      The operation for Kevin's example could be 4-sided patch/Multiblend/Edge Surface, or whatever name you want to give that particular scenario.

                                                       

                                                      The operation below that is one that I have never used. It may be very helpful to me once I'm able to wrap my head around why I would setup geometry that way, but I don't setup my geometry in this way currently. To me this is a different operation, not sure what to call it.

                                                       

                                                      I couldn't agree more with your last comment. You need better demonstrations of what people can do with the software. When you install XNURBS you get a toolbar with one button and the only picture on the website homepage shows a SWX fill type scenario.

                                                       

                                                      Finally, I believe that keeping dialogue like this going and listening to this feedback from some very respected long-time SWX users could benefit your company greatly. If you implement suggestions from these very experienced users I believe your product will benefit greatly and will see more success.

                                                        • Re: XNurbs - further investigations
                                                          X. Liu

                                                          Hello Mr. Landsaat,

                                                           

                                                          Many thanks for your comments.

                                                           

                                                          “SWX often times creates incredibly dense UV surface patches with a wobbly rippled surface.”

                                                          If you use xNURBS for those models, xNURBS should fix the problems you mentioned, e.g., “the wobbly rippled surface” etc.

                                                           

                                                          There are thousands of operations or scenarios how xNURBS could be used. The following is an example of blending/Lofting generated by xNURBS V2 (G2 continuity and 0.0003 mm tolerance). It shows the trimmed surface and the untrimmed surface (i.e., 4-sided. As marked in the images, V2 can generate the optimized results for both.). Which one is better? I guess this option is what you look for?

                                                                                  Trimmed

                                                          Preview(Trimmed).png

                                                          Zebra(Trimmed).png

                                                                                          Untrimmed

                                                          Preview(Untrimmed).png

                                                          Zebra(Untrimmed).png

                                                          Do not try to re-edit the attached Trimmed.SLDPRT and Untrimmed.SLDPRT: since all V1 users will get a free upgrade to V2, so there is no warning if you try to edit V2 features with V1 addon (there is no such a scenario).

                                                           

                                                          SolidWorks did suggest that we need better demonstrations to show how to use xNURBS. However, there are literally so many different types of operations and it is impossible to demonstrate all of them. From users’ viewpoint, all operations or scenarios are the same: just select curves or points, xNURBS will produce the best results from your input.

                                                           

                                                          “NX runs on the same Parasolid kernel as SolidWorks so clearly the geometry kernel has much better surfacing capabilities than what we have with SWX features.”

                                                           

                                                          Parasolid used by NX is the same as SolidWorks. NX develops some other surfacing tech, e.g., variational surfacing, which partially came from SDRC or I-DEAS software. (The tech produces fair shapes that are analogous to a physical model: when a wooden batten bends, it always assumes a shape that minimizes its bending energy to form a smooth curve. So this is why NX has better surfacing capabilities as you said.) xNURBS is also based on variational surfacing, but its variational surfacing tech is way more powerful than NX’s own variational surfacing. (NX R&D teams use what they call “stiffness matrix” – a primitive tech of variational surfacing … ) If you are happy with NX surfacing capabilities, then you should be happier with xNURBS.

                                                           

                                                          While xNURBS may provide the ultimate solution for SolidWorks surfacing, but it seems that SolidWorks needs to reach some agreement with Dassault. You may wonder why giant Dassault would intervene the process of our xNURBS application: Catia R&D teams started working on their variational surfacing tech in 1990s, so they know we made the breakthrough and the importance of the tech … I believe that SolidWorks wants its users can use xNURBS tech and I believe ‘they work very hard on our application’ as they claimed, but they have discussed our application for quite a while. I am not sure how to speed up their discussion.

                                                           

                                                          Dr. Liu

                                                            • Re: XNurbs - further investigations
                                                              Mark Landsaat

                                                              Thanks for the response Mr. Liu, it does seem a little like we go round and round on this discussion.

                                                               

                                                              "SolidWorks did suggest that we need better demonstrations to show how to use xNURBS. However, there are literally so many different types of operations and it is impossible to demonstrate all of them. From users’ viewpoint, all operations or scenarios are the same: just select curves or points, xNURBS will produce the best results from your input."

                                                               

                                                              Several users have suggested better demonstrations and according to your reply even SolidWorks has suggested this. There's a lot of middle ground between "impossible to demonstrate all of them" and one highly theoretical example on the XNurbs homepage. Kevin's example that started this thread is a great example of a real world application. Showing several real world applications/solutions will help users understand how this would fit in their workflow.

                                                               

                                                              With regards to your last comment, I can totally see why Dassault would not want to allow XNurbs as an add-in to SolidWorks if it is indeed a superior solution. This would basically mean there's no longer a need for companies to pay astronomical license fees for Catia, but can instead use SolidWorks with the XNurbs plug-in.

                                                              I'm going to hold out on purchasing the plug-in and wait at least until you can officially release V2. The reason I will wait is that I have been burned with plug-ins before. T-Splines for Rhino was purchased by Autodesk and killed, VSR Shape modelling for Rhino was also purchased by Autodesk and killed. It seems to me that there's a good chance Dassault might block XNurbs if they feel it could potentially keep people from purchasing Catia. Even purchasing V2 will be a risk since Dassault can essentially block your plug-in anytime they want, but it may be worth it to me.

                                                                • Re: XNurbs - further investigations
                                                                  X. Liu

                                                                  We disabled our purchasing button a while ago when we found out that our xNURBS application was not processed normally. So you cannot purchase xNURBS addon right now. (We have been in business for more than a decade and know how to be a responsible party.)

                                                                   

                                                                  "I can totally see why Dassault would not want to allow XNurbs as an add-in to SolidWorks if it is indeed a superior solution. ... It seems to me that there's a good chance Dassault might block XNurbs ..."

                                                                  It might not be the case. As already mentioned, xNURBS variational surfacing tech is way more powerful than NX’s own variational surfacing. Do you think Catia’s variational surfacing could be that powerful? If Dassault would simply block xNURBS, then we obviously would work closely with others and others would have surfacing capabilities that Catia might not be able to compete with. This may be the worst scenario for Dassault and I am afraid that Dassault won’t do it.

                                                                   

                                                                  You are very frank about Dassault. To be fair, SolidWorks does want to address its surfacing capabilities, and to my knowledge, SolidWorks is ‘asking strongly to approve xNURBS application’. Nevertheless, it is a bit out-of-line to ask us to wait so long and we had to repeatedly re-schedule our products’ release.

                                                                   

                                                                  We will soon release new products, including Rhino plug-in. V2 should work with SolidWorks in the foreseeable future, e.g., SolidWorks 2020, … SolidWorks 2030 etc.

                                                                    • Re: XNurbs - further investigations
                                                                      Mark Landsaat

                                                                      Well, you make some good points regarding making this available to the competition, I hope you will get this resolved soon. At the same time you confirm my concern with plug-ins in general. If Dassault for some reason would not want this implemented in
                                                                      SolidWorks and you decided to sell your plug-in intellectual property to Siemens or Autodesk it would leave SolidWorks and Rhino users with another dead end plug-in, T-Splines being the prime example of this scenario.

                                                                       

                                                                      But I am interested in both plug-in versions, SolidWorks and Rhino.

                                                                       

                                                                      While both VSR Shape modeling and T-Splines for Rhino are dead as plug-ins, I have Rhino 5 running on my machine so I can continue to use both even though both were killed off by Autodesk several years ago.

                                                                       

                                                                      Looking forward to the new releases.

                                                        • Re: XNurbs - further investigations
                                                          X. Liu

                                                          We have officially released V2, and as we promised several months ago, our V1.X users are entitled to get a free upgrade to V2.X.

                                                           

                                                          The attached PDF is “What’s New”. Compared with V1, V2 produces a better result from the same input, i.e., V2 can use less control points to achieve better surface quality and smaller deviation: For example, for Kevin's example that started this thread, to satisfy the same input, V1 needs 24 X 27 (648) control points and achieves 0.0018 mm deviation; V2 needs 21 X 24 (504) control points and achieves 0.0008 mm deviation.

                                                           

                                                          Tip: When using V2, dragging “Flatness Control” to the right should generate a smoother surface with a better Zebra view.

                                                           

                                                          Hope our users can enjoy the new release!