Want your opinion on Sketching - a debate

[ROK99]

Sketcher is a critical tool for modeling - perhaps the most important.

But when the first feature in your model is going to be a primitive (i.e. block, cylinder, etc.) do you actually sketch the block or sketch the cylinder?

Primitives should NEVER be used for anything other than the initial feature, but is it worth sketching, constraining, and then extruding/rotating a feature, when it is already available as a base feature in NX ?

We are debating this at my company.
Want to see what most people think...

For instance:
To make a “Square Head” pipe plug, you can make it two ways:

With 2 features:
Cylinder (0)
Rectangular Pad (1)

With 4 features:
Sketch (0)
Revolve (1)
Sketch (2)
Extrude (3)

 

[ROK99]

I say, that the Cylinder and Pad are fully-parametric.
Why do something with 4 features that you can do in 2?

 

[JohnRBaker]

Of course, if the Sketches were created 'internal' to the Revolve and Extrude features, which is the default behavior of NX, it would be, for all intents and purposes, as if there were only two features.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[NutAce]

And don't forget that a Primitive is not really fully constraint... you can move it around pretty easily.

Ronald van den Broek
Mechanical Engineer
Cad Environment Coordinator
Wärtsilä, Propulsion Services
NX8.5.3 / TC9.1.2
HPZ420 Intel(R) Xeon(R) CPU E5-1620 0 @ 3.60GHz, 32 Gb Win7 64B
Nvidea Quadro4000 2048MB DDR5
HP EliteBook 8570W Intel(R) Core(TM) I7-3740QM CPU @ 2.70GHz, 16Gb Win7 64B

 

[JohnRBaker]

That's not a true was it once was. For several releases now, the so-called 'Primitive' features have been FULLY-parametric, including the ability to associate their positions relative to other objects or even to a parametric set of X,Y,Z values.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[KhimaniMohiki]

Maybe in previous versions of NX primitives shouldn't have been used for anything but the first feature but now since their position is associative I don't see a problem with using them in regular modelling. I would use them to create bosses on castings and mouldings, associated to a CSYS then instance to other CSYS on the part, I found it quicker and a bit more stable than sketching.

Khimani Mohiki
Design Engineer - Aston Martin
NX8.5

 

[carlharr]

We always said only one primitive, used as first feature (which they are good for).

But then they caught me by surprise when I tried to demo why they shouldn't be used as a second feature, and they worked fine because they've been improved!

No problem with primitives as first feature at all.

http://www.jcb.com

NX 8.5 with TC 8.3

 

[RobLN]

Personally in all my time modelling I have never used a primitive object, always just gone from scratch from the first sketch. I make many varied designs in sheet metal and normal modelling and cannot see the advantage in saving 2 steps considering the whole modelling time taken for a finished part. It is just not something I have ever used.
I also prefer the flexibility of the base sketch, for instance I can always go back and re-visit it to add in extra detail that would save me cuts, rounds or other features further down the line.

Rob.

Solid Edge; I-Deas 7 to 12; NX4, NX5 NX6 & currently NX7.5 / TeamCenter 9.1 & Ansys 14.5 on 6GB Windows 7.

 

[aluminum2]

I would argue about primitives being more stable than sketching which was said earlier. It more or less comes down to your modeling techniques.. Either method is useful and has it's place. What I like about sketches is that it does a better job of mapping out geometry that other people can use down the line. When 3 other divisions have to link the model then that is important.

 

[JNieman]

6 of one, half dozen the other.

_________________________________________
NX8.0, Solidworks 2014, AutoCAD, Enovia V5

 

[ewh]

I agree with JNieman... I can create bosses, holes, slots, etc which are fully parametric and easy to edit more quickly than if I sketched each one out.
I have gotten into the habit of only starting with one primative though where a more complex feature isn't required.

“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV