20 Replies Latest reply on Nov 25, 2013 1:01 PM by Eric Irwin

    How do I create smoother surfaces

    Hayden Krause

      Hello SW community,

       

      First time on forums – I hope some1 can help. 

       

      I have a surfacing issue.  I would like to try and improve the quality of one of my surfaces.  I have tried many things but can’t get the surface to “smooth out”. 

      The model is attached and the surface I am interested in improving is highlighted in blue below (you may be able to see that the surface is un-smooth).  The model is attached. 

       

       

      Untitled.jpg

       

      Is there any1 that can help me with this surface? Or anyone that can offer some guidance as to how to go about this particular surface?

       

      One thing I have noticed is that when the surfaces are knitted together the quality of the surface is reduced.  You will be able to see this in the model by supressing the knit feature at the bottom.

       

      Cheers!

       

      Hayden

        • Re: How do I create smoother surfaces
          Eric Irwin

          Try a Boundary Surface instead, tangent on left and right (of above image) and tangency influence turned up to 100%.  Looks to be nearly curvature continuous.

            • Re: How do I create smoother surfaces
              Hayden Krause

              Eric,

               

              Thanks for your reply.  I have tried Boundary surface and the curvature continuity is not sufficient.  Looking at the model you sent there still seem to be some undulations (though slightly improved).  I have read that boundary surface should be used for 4 sided boundary - so I shall stick with this from now.

               

              I have been playing with the model.  The boundary surface seems to work best if all the constraining lines are continuous (as one would expect I suppose).  The problem seems to be that one of the lines is not continuous.  I have replaced the non-continuous line with a continuous one and this has created a perfect surface. 

               

              cont.png

               

              Hayden

                • Re: How do I create smoother surfaces
                  Eric Irwin

                  Hayden,

                   

                  You are thinking of continuous and non-continuous in the wrong way.  An edge/boundary can be made up of tangent entities and it will work fine.  In order to get the surface to be "curvature continuous" with the surface next to it, the curves should be curvature continuous with the surface next to it.

                   

                  To evaluate the surface quality you should be using the Curvature analysis tool and the Zebra analysis tool, not just looking at reflections withing your model.  The analysis tools are much more reliable than the graphics from the standard screen.

                   

                  Boundary surface is my preffered tool, mostly because you have more control.  Essentially it can do everything that a Loft can do, but has more control.  There are times when it is recommended to use Loft instead, but I can't think of those right now.

                  • Re: How do I create smoother surfaces
                    Roland Schwarz

                    You are creating a surface using fillet edges as part of the definition.  That is a staple ingredient in surfacing disasters.

                     

                    If you can, imagine what the surfaces would be without those fillets in they way and definie wour surface accordingly.

                      • Re: How do I create smoother surfaces
                        Hayden Krause

                        Roland,

                         

                        Thanks for your reply.  Im not sure I understand what you mean.  There are no fillet commands in the model though there are some surfaces that are created for that purpose. 

                         

                        Would you suggest creating the model as a square - then adding the fillets at the end?

                         

                        Hayden

                          • Re: How do I create smoother surfaces
                            Eric Irwin

                            Hayden,

                             

                            Yes, I think you understand what Roland is trying to say.  If it were me, and I was as concerned about the quality of the side surface as you seem to be, I would create the side surfaces and the bottom surface and then the transition that is joining them.  That does depend a little on how important the joining transition lines are.

                             

                            The short answer is that with surfacing, it is usually better to start with larger and more consistent surfaces that are overbuilt (if needed) and then trim them back using smaller transitional surfaces.  That will help improve your surface quality.  There are times that this cannot be done, but it is a good general practice.  It appears you are trying to build exactly what you need right out of the gate and then knit them all together and be done.  Instead I try to tell people to approach it like you were modeling in clay.  You would get the big surfaces in and smooth, then you would come back and add the details.  In the end, it is very much like solid modeling, where your fillets are added at the end.  Not quite as cut and dry as that, but similar in philosophy.

                             

                            I hope that makes some sense.