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Re: Continuing surfaces with adjacent poles

Gears Phenom Gears Phenom
Gears Phenom
@LukeBr,

Looking a bit closer at some of your images, from where did the original aircraft model originate? I ask because I'm simply amazed at how few surfaces there are considering all the shapes. Most Class A models that I see in the auto industry have many more surfaces - the fuselage area behind the cockpit windshield would have been at least 5 surfaces (3 slabs and 2 blends) on the upper portion alone, excluding any that were built with the intent to mirror from right to left sides.
Tim
NX 11.0.2.7 MP11 Rev. A
GM TcE v11.2.3.1
GM GPDL v11-A.3.6

Re: Continuing surfaces with adjacent poles

Genius
Genius

Hi @TimF   Got it. Thank you!

Re: Continuing surfaces with adjacent poles

Experimenter
Experimenter
Thank you for the tips. I am aware that 3 sided surfaces cause trouble in NX. I know it's easier to make an "almost 3 sided" surface with a 4 side sirface, but thats not what I want to achieve. But I am trying to recreate the surface that is theoretically possible (and is proven in the original model) but it seems it's impossible to build in NX or I don't know how.

Re: Continuing surfaces with adjacent poles

Experimenter
Experimenter

The original model is a Grabcad STEP model of the Cessna 404. Can be found here https://grabcad.com/library/cessna-404-1 ( I just untrimmed the details to get to the core body surfaces and hid the rest). It was probably not made in NX but I am trying to get more into advanced surfacing ( aerospace industry) so as a training I took a model and tried to recreate it in NX. Turns out, some surfaces (seamingly ordinary and simple) cannot be replicated or at least using basic NX commands and not using complicated workarounds.

 

I apreciate your help! thank you.

Re: Continuing surfaces with adjacent poles

Valued Contributor
Valued Contributor
I think I found out what he did.
I pretty sure that no software will give you that output whatsoever.
The "old" / "more mechanical" way of doing this is to do a x-form after you create the surface but where to??

Well an old technique to achieve continuity was to extend some isoparameter curve from the surface and snap onto their pole to get continuity. It should work in that case.

If your goal is to achieve better quality surface... I would not use that as a reference... This is not good practice or Class A surface

Re: Continuing surfaces with adjacent poles

Gears Phenom Gears Phenom
Gears Phenom

@LukeBr

 

Complicated workarounds?  Sounds like you have pretty high expectations as far as how easy this should be.  If it were as simple as you make it sound, don't you think more than 2 people would be offering suggestions to try and ease you into this type of modeling?

 

Sorry, but easy is typically not what Class A modeling is.  It's complicated, lots of refinement is usually required and attention to minute details is a must.  If you don't like that sort of work, then maybe it's not for you.  You're not going to find any software out there that makes this sort of modeling any easier either....math just doesn't change like that.

 

Go watch some You Tube videos of people using Alias to create automotive body surfaces (not some enthusiast with a cracked copy of NX trying to trace over line art of a Ferrari) and you'll see it's not so simple and they also have to create, check and refine the surfaces throughout the whole process.

Tim
NX 11.0.2.7 MP11 Rev. A
GM TcE v11.2.3.1
GM GPDL v11-A.3.6

Re: Continuing surfaces with adjacent poles

Siemens Valued Contributor Siemens Valued Contributor
Siemens Valued Contributor
In general three sided surfaces are not recommended in any Cad/cam system, specifically if you are going to offset or make a solid out of them.
Many people in the styling industry prefer to make four sided surfaces and not make one side very small (.002) as future Pole manipulation well return bad results, generally users will make very large four sided surfaces in a very simple form trim them to the three sided result


Barry
Barry Waldie