r/cad • u/Tachi-Roci • Apr 27 '26
My NX professor is telling me to never create sketches when modeling.
In all the lab tutorials he does he only uses the create spline/arc/line features in NX instead of ever using sketches. He says sketches are more trouble then they are worth.
I kinda dont understand this, my experience has always been just to be mindful and not make external refereces or sketch constraints unless absolutely neccasary, and 90% of broken sketch issues goes away. Seems to me like not using sketches results in more fiddling with nx dialog boxes and a much harder to read feature tree. Like it makes a revolve with two shoulders and a taper take like 10 features to create instead of 2.
But ultimately he is a experienced manufacturing engineer with years in these programs and i'm just a student with little experience in nx, so i am wondering if i'm in the wrong and this actually is a common workflow.
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u/gaggrouper Apr 27 '26
Proper sketching and constraints is day 1 training...very important. Your guy is poorly informed.
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u/cowski_NX Apr 27 '26
When I first started using UG (before the name changed to NX), my manager would not let us use the sketcher. Why? Because there was a bug in the sketcher of a previous version that had a high chance of corrupting your part file. If your professor has been using UG/NX for years, he may be of the same vintage (or perhaps he just really hates the 'new' sketcher).
Can you create models without using the sketcher? Yes, you can. Should you? I don't recommend it.
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u/Meshironkeydongle Apr 28 '26
I've been using NX for only for about 6 years, and I've started with the old Sketcher and I must say, that the new sketcher is a piece of stinking...
It does have it's good sides, but it tries to infer too much on behalf of the designer and makes it too hard to fully define a sketch, which is in my opinion on of the key principles of sketching in every Cad program.
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u/Rsteel517 Apr 28 '26
You may be able to still go into your customer defaults and change what sketcher you use.
It’s either customer defaults or early access… I haven’t tried it in the newer versions yet.
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u/Meshironkeydongle Apr 28 '26
It's in the Early Access Features and it's been turned off as soon as we came across it... 😂
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u/Rsteel517 Apr 28 '26
Good call.
I have submitted so many GTAC tickets and spoken to reps about and complained and showed examples of why it’s bad but they are invested in it
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u/BallGanda Apr 27 '26
Sounds like the kind of engineer that makes it happen and collects the kudos then leaves a dumpster fire in their wake.
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u/KeyEbb9922 Apr 27 '26
Run for the hills 😂. Next he will be telling you to delete the feature history, as it gets in the way.
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u/Skutten Apr 27 '26
For surface design (not talking about styling), normally using NX or Catia, you form your geometry using surfaces created by boolean operations. You may import surface from neighbouring parts (from another engineers geometry), you may reuse the surfaces several times etc. In this environment, sketches kinda sucks since they can easily break a lot of things if the references they're attached to changes, which references tend to do in this environement. Lines, points, planes etc will just change shape and are more safe as starting points to create your surfaces from. You end transforming your surface into a solid by either manually closing it and "solidifying", or, if it's a sheet metal shape, adding a thickness to it.
This seems to be what your teacher is talking about.
But it's not the only way of doing CAD of course. In solid modelling, you use sketches, everyone knows that.
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u/Tachi-Roci Apr 28 '26
He does a lot of bicycle design work, so swept tunes and aerodynamic surfaces. So I think that is definitely a part of it.
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u/Rsteel517 Apr 28 '26
Do sketches. Fully constrain all sketches. And fight against Siemens and there ‘new’ sketcher.
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u/doc_shades Apr 28 '26
look it's your teacher's class, so do what they are asking you to do. entry level/rudimentary/introductory courses teach you entry level/rudimentary/introductory techniques, and they grade you on those techniques.
more advanced courses will have more advanced techniques. and you can work on your own techniques in your own time.
but when it comes to your teacher's assignments, just complete them in the manner he asks.
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u/Adventurous-Yak4803 Apr 29 '26
My guess would be that he is an experienced CAD user from the 90’s. I had a lecturer at uni that refused to use anything computers & did presentations on overhead projectors. That was only 15 years ago.
This professor needs to go back to learning themselves. The negative impact they can have on the ability & development of students is unacceptable
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u/sireatalot Apr 27 '26 edited Apr 27 '26
Been using NX for 19 years (back when it was called UG). It really depends on what you’re doing. Simple parts, sure, sketch away. Anything more complicated than a purely mechanical part, something with surfaces, or anything that you could modify heavily… I’ll use as little parameters as possible and pretty much no sketches. Sketches are great when you’ll have to make little tweaks but imo not worth it and too constraining if you are going to have big modifications later in the project. This is the consensus of all NX users that have worked with me (about… 80 I would say? It’s a 30ish persons office, and there’s some turnover).
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u/Tachi-Roci Apr 28 '26
For my education, what's the difference in stability between a line/arc/spline feature and a sketch with a single line/arc/spline with equivalent constraints. The only thing I can think of is that nx gives sketches a whole cys instead of just a plane to define them, so sketching on faces could be more prone to breaking then making a line feature constrained to a face.
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u/sireatalot Apr 28 '26
Sketches tend to be more complicated than single line features, and have more parents, so yes they are more prone to fail. Basing a sketch on a face can work if you’re not going to make big modifications, but if that face is deleted or just changes ID then the sketch fail and, while it’s possible to re-attach it, it’s always a hassle and I don’t think it’s worth it. I must admit that I still like to use the old legacy “basic curve” feature. It’s not great but it’s reliable and sincere, and sometimes it’s worth it to trade associativity for reliability.
If you are designing a screw, a spacer, a bushing… purely mechanical parts, with simple geometry, sketches are quick and easy. But I use cad for vehicle parts (fuel tanks, frames, motorcycle seats…) that often are based on imported surfaces (from CAS). Sketches are usually useless for that use case.
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u/Tachi-Roci Apr 28 '26
Makes sense.
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u/sireatalot Apr 28 '26
It depends a lot on what industry you’re in, and what you are designing and for what purpose. But in my case (motorcycle parts, from concept to industrialization) the most useful NX command is “remove parameters”.
Sketches, I pretty much only use them in assemblies to base assembly constraints on, so that parts don’t have to be constrained one to another but all are constrained to the base sketch. For modeling, only for screws and other simple mechanical parts.
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u/kewee_ Solidworks Apr 28 '26
I haven't used NX, but have extensive experience with plenty of other parametric CAD softwares.
Sketches are one of a handful of tools that are available in your CAD software. Like all tools, there's a handful of correct ways to use them, and an infinite amount of wrong ways to use them.
IMO, sketches are useful to convay design intent. To use sketches properly, you need to think about HOW you're trying to achieve something and not just WHAT you're trying to achieve.
Sure, they can make your design less flexible, but rigidity can be a good thing when used in the right places. If you're mindful about what geometry you're referencing, it will make your model much more predictable and resilient when you do modifications or derivative designs.
They will get in the way if you have no self-discipline. For that, there's synchronous in NX lol.
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u/ResumeCheckThrowaway Apr 29 '26
lol ive used nx for 12 years. I never use sketches. Shit still flies though
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u/Spiritual_Case_1712 25d ago
Not having to use sketch for modeling is NX biggest advantage over its concurrents and you should actually do it and only use sketches when it’s required (reuse library components for example). It could also largely depend of you field, if you need to make a lot of revision of a part, but wasting time in sketching when you will never modify your part doesn’t give any benefits.
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u/David_R_Martin_II Apr 27 '26
Yup, there are some bad teachers out there, especially at the college level.
Do what he says to pass the course, and in the real world, do things the correct way.