CATIA ICEM surf and solidThinking Evolve, are they same ?

Altair Forum User

Hello guys, I need your help in this context. CATIA 'imagine and shape' and solidThinking Evolve are these same? Are both used for class A surfacing? What are relative advantages and limitations of these two softwares?

Thank you in advance 

Altair Forum User

solidThinking Evolve is not used for class A surfacing

Altair Forum User

What is class A surfacing? Are there any other  classes of surfacing? (Like class B or class C). As solidThinking Evolve uses PolyNURBS tool, what kind of surfacing we can do in evolve?

Please help.

Thanks

chaos_chord

Well SolidWorks would not agree with you /emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20'> If you are coming from SolidWorks background and you just want more control over your surfaces 3DS suggests you use SolidThinking Evolve and it classifies it as class A surface modeler. Check it out yourself LINK

I'm pretty sure you can pull off a class A surface in Evolve with nurbs cause nurbs foundation is as same as it is in Alias. Once you venture into multisweeps and multiple rails then it's questionable how much of a control you have to pull of a ultra high quality surface. Maybe some of the sTE people can reply on that one. 

It also depends from which spectrum you are coming from, if you are a product designer then go ahead and use Evolve cause it's ten times more natural and faster than Alias or any other established surface A tool. Advantage of Evolve or Rhino is that you can jump into the fire right away and walkaway with the finished product quite fast. Good luck doing that in certified class A surface tool such as NX or CATIA, I for once can't even choose the right version of CATIA cause there are so many modules, versions and what not. If you are a designer you also have the benefit of sending your model to engineers who already work in Alias or similar and they will rebuild the surface anyway if it needs rebuilding.

And then there is big BUT. Class A surfaces are all nice and dandy but outside of transport industry very few consumer products do include ultra high quality surfaces. Take your average Dell/HP/Lenovo laptops and look at those side edges, it's obvious with the naked eye that there are some distortions in transition. That could be a mistake in modeling or in production due to cost cutting.

ArjunA_22390

Class A surfacing is a methodology and modeling technique. Evolve contains some concepts of class A modeling like curvature continuity but is not the ideal tool for creating flawless surfaces, like those you see on automobiles. The inherent quality of class A surface is its ideal CV distribution. Certain tools in Evolve are based on parasolid(same engine as solidWorks) and deliver undesired CV distribution that can later be partially redistributed. Evolve has construction history, that makes it hard to redistribute points while maintaining dependencies. Most programs like Alias, leader in Class A surfacing, requires you to delete the history before manual manipulation of CVs. However, the nomenclature is slightly flawed. Everyone knows that to achieve a class A surface, the underlying curve must be of the highest quality. Therefore, your curves must contain the least number of CV's and show smooth curvature. See image attached.

 

If you use the top curve to create surfaces, the output will be low quality. The bottom curve has a very close shape but with better CV distribution. Hence, while creating curves, use the curve plot tool - shortcut -SHFT+CTRL(CMD)+P and check the quality of the curve. 

For product design, class A surfacing is not a mandate, unless you are talking about Apple, that is very particular on surface quality. You can achieve good surface quality in Evolve at the expense of time. 

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chaos_chord

Thanks for the clarification.

I know this is not the best place on forum to ask this but do you plan to give option to add more than two CVs per one MetaCURVE segment? Or MetaCRUVE is just a NURBS curve with different control?

Darren Chilton_21533

Sorry for the late reply.  Just saw this open question.

The MetaCurve will eventually be completely replaced by the Blend Curve as we add more and more features and options to it.  As a result you will be able to achieve what you are looking for.

And just some additional information regarding Class A surfacing.  There is generally a lot of confusion about what what it is, what it means, and how to achieve it.  There are 'A' surfaces and 'B' surfaces.  'A' surfaces just means the visible/aesthetic side of the model, and 'B' surfaces are the side of the model you can't see.  Take a computer mouse for example:  The exterior surfaces that you can see and touch are all 'A' side surfaces, whereas the inside faces of those pieces are all 'B' side surfaces.

The confusion comes in when you start trying to define mathematically what Class A means.  For every company and product the definition can be different.  For some the definition can be as simple as tangential (G1) continuity as their minimum requirement, where others may require a minimum of curvature continuous (G2), or curvature continuous (G3).  These are all technically Class A surfaces, but due to the automotive influence in the design culture most people associate Class A with G2 continuity or higher.  But you also have to keep in mind that the higher the level of continuity the higher the chances are to introduce 'wavy' surfaces because the modeler has to manage more and more points and their relationships to each other.  So just because a surface is mathematically G3 doesn't necessarily mean it is the desired shape.  There are a lot of things that I could get into on this, but I will leave it here for now.

So can Evolve be used for Class A surfacing?  Absolutely.  We have customers all over the world doing this on a whole range of products.  Our tools such as Loft, Sweep, Patch, Round, etc...all have options for G2 continuity.  The only exception  for Class A surfacing with Evolve would be automotive exterior stamped sheet-metal, which is a very special case where additional tools and control are needed and the Class A definition requirements are much higher.

Hope that helps.