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Are SolidWorks surfaces good enough?

Question asked by Kevin Quigley on Mar 5, 2011
Latest reply on Apr 28, 2011 by eric fairbanks

That might be an odd title for a thread but let me explain. I am currently looking at ways we can speed up and enhance the quality of our modelling work from conceptual design through to production surfaces. As part of this process I have been looking at several different packages and last week I spent a day with an Alias expert to see what that app could offer.


Now I am familiar with surfacing only systems and the general methodologies of working with surfaces - we also use Ashlar-vellum Cobalt, Shark FX and VX here - all of which have good 3D surfacing capabilities - but I am trying to focus everything into Solidworks as I really see that as being the most efficient way. I am comfortable with Solidworks and the surfacing in that but I do find it a bit cumbersome for conceptual design, and frequently wish the spline creation and controls were a bit more reliable and flexible. We have been looking at Rhino as well, but the lack of associativity to surfaces and constraints to curves is limiting. Hence why I looked at Alias.


Any product designer out there will have heard of Alias, and it is still widely used in many big name design businesses. The guy who I visited had worked as an auto designer for many years and then moved into training where he trains all the big name auto companies in Europe - he knows his stuff. He showed me how he would approach a product I designed in Solidworks, and he worked through the process in Alias. We looked at the imported Solidworks surface data and that is partly my question.


I was quite frankly horrified by the surfaces as imported into Alias. To create this particular object I used boundary surfaces and fills - all generated from a two point spline (so literally a point at the start and a point at the end, with directional and constraint controls) In SolidWorks the curves are smooth, the surfaces looked smooth and G2 continuous. In Alias they looked smooth on the shaded preview but the wires showed hundreds of UVs on the fill surface. We then remodelled the worst section of the product in Alias (his comment was - modelling in Alias is slower than Solidworks, but better in terms of quality). He spent some time setting up the curves, ensuring continuity then surfacing. The IGES file I exported from SolidWorks was 11MB. The IGES file from Alias was 300kb.


I came out of the day having learned a lot and thinking that maybe I did need to "up my game" and get into Alias. But back to the thread title - does it really matter? Working in surfaces in SolidWorks you are kind of led a lot of the time - which is good, but you cannot really tell how good your surfaces actually are from a density of points perspective. Similarly, creating 3D curves in SolidWorks is relatively easy, but the controls are nowhere near as intuitive or flexible as they are in say Rhino. The point is I am careful, I take time to set up curves and surfaces. It all looks OK in Solidworks, but is it really? Am I really just seeing the glossy paint covering up the dodgy brickwork? I don't know. All I know is what I saw with my own eyes.


Personally I think if you are designing small objects then it is not that critical. Surface continuity on a handheld part is less critical on something the size of a car body. But on those larger parts (that I do work on) I am starting to doubt what I am producing - and that is a worry to me. Up to now I have always said, if it looks good in Solidworks it is OK - maybe that is not actually the case?


As this evaluation process continues I am seeing some serious defficiencies in SolidWorks that really ought to be addressed:


1. Lack of UV/iso curve visibility - why can't we defined the number of UV/iso curves as a view option? Even the $99 ViaCad has this - every other CAD system I have has this. SolidWorks doesn't outside of surface previews during creation. This really is the first item in looking at a surface.


2. We need more and better evaluation tools for 3D curves and surfaces. Alias, for example, has a great surface shader allowing you to move the lights around, and another that creates an iso curve on the surface at any angle with curvature spline and numerical deviation details.


3. We need better 3D curve creation and editing tools. I use a 2 point spline most of the time because anything else is just too hard to do. Surface demos usually have long slender parts with multiple spline points. In reality many parts are more subtle than that, and require tweaking of points. Again taking Alias as an example they have a lovely scaled move CV command - where you adjust the scale of the effect of the movement of your mouse to the movement of control point - makes for very easy precision control.


4. Display of surface internal points - this was the shocker! Just showing all the points showed up the density of points used by the fill surface and to some extent to the boundary surface. Again in Alias (and others) you can show surface control points as you shape it, adjusting the points to make the "flow" better.


Bottom line. If all this was added to SW premium it would be a no brainer upgrade. As it is I am left thinking perhaps I need to look elsewhere to do this kind of quality surfacing work. Which is not what I want to do, but perhaps what I need to do to get to the next level?


Be interested to hear from others.