7 Replies Latest reply on May 27, 2009 10:16 PM by Kevin Quigley

    Controlling isoparametric curves

    Kevin De Smet
      I am wondering whether it is possible to control the amount of isoparametric curves when doing a boundary or fill feature. I wouldn't ask this if it weren't for the sketch tool " Face Curves" which already kind of does this, and of course, kind of not.

      I haven't had any trouble with the surfaces I've created letting SolidWorks take care of that for me, which is awesome. But if I would - could I?

      Is there a workflow that involves the Face Curves tool for this purpose?
        • Controlling isoparametric curves
          Kevin Quigley
          I'm not sure what the answer to your question is Kevin, but one thing I find frustrating in SW is the lack of a simple view toggle to turn iso curves on or off. In most surfacing based applications I use (and many solids) iso curves can be turned on or off by a simple view preference or check box whilst working live. In most you can also set the iso curve density by surface or object. This is VERY useful for seeing how a surface flows. Face curves just don't do it for me.

          I have attached a link to a short video (no sound) showing how it is done in Ashlar-Vellum Cobalt.

          Here I created a simple surface from 3 splines, toggle the display of iso curves on and off, change the number of curves interactively and edit the surface showing how the curves update. Finally I show how you can use the explode edge tool to extract any iso curve to a spline. Now you can do all that in SolidWorks, but it takes a lot longer and is less intuitive.

          http://www.screencast.com/t/qquOSZnxtd
          • Controlling isoparametric curves
            Kevin De Smet
            That's indeed what I am looking for - in your video though I don't understand one thing: The surface stays the same whether it has 0 or 10 isoparms in both directions. Shouldn't 0 isoparms give you a flat surface and 10 isoparms a very smooth interpolated surface?
            • Controlling isoparametric curves
              Robert Stupplebeen
              It looks like simply viewing the additional isoparms does not change the surface but once they are visible you can modify them and in turn modify the surface. This work flow outside of the feature manager probably goes against SW's history based paradigm.
              • Controlling isoparametric curves
                Kevin Quigley
                The number if iso curves on the surface does not affect the quality of the surface. The number of control curves that make up the surface affect the surface quality. iso curves are generally used as a viewing and evaluation method to let the user see how the surface flows. Control curves that make the surface (eg the number of points on the splines) are what really affect the quality of the surface. Generally the fewer the better.

                What the video shows is how easy it is to show and edit the iso curves for surface evaluation.

                The bit where I am exploding the iso curve to a spline is really just there to show a similar application of face curves in SolidWorks. In Cobalt you can do this interactively, but the exploded iso curve does not retain associativity to the surface or iso curve it came from. It is still useful though for rebuilding a surface or for adding quick and dirty surface details.
                • Controlling isoparametric curves
                  Charles Culp
                  Kevin,

                  I think the "gap in understanding" here is that with NURBS, unlike mesh data, you are not just defining the edges where the curves are, you are actually defining the entire surface. So whether there are "curves" in the middle or not is irrelevant, the entire surface is defined. This is why you can do the "face curves" command, and get the curves at any location along the surface.
                  • Controlling isoparametric curves
                    Kevin,

                    Perhaps I could address the question behind your question: looking for more control in the surface? In Boundary, for instance, if what you are looking for is better control of the flow of the surface, then have you tried the "Connectors" in the Boundary Feature? Connectors allow you to do some amazing stuff with Boundary surfaces. You can add as many connectors (in both directions) to control the "flow" of the UV of the surface. These combined with the tangent influence options allows you to more predictibilty control your surface. Additionally, if you want more control, you can use our freeform tool to further tweek the surface after you've created it to get even more control over it.

                    The face curves have traditionally been used by SW users to see a persistent UV mesh of the surface (although that isn't entirely accurate.) We do have UV mesh in Fill, Boundary and Freeform while editing the feature, but they are, of course, not persistent.

                    hope this helps.
                    • Controlling isoparametric curves
                      Kevin Quigley
                      Mark, any chance of getting a iso curve view menu control like Cobalt's into SW2010

                      Kevin (the other Kevin - I'm getting confused here!!) another tricj to seeing the surface flow is to use zebra stripe evaluation with very thin stripes. This is not quite the same thing but it does the job sometimes.