Non oriented Surface in NX 11

[James93]

Hello, i want to create a sphere with holes that are connected with a moebius-strip-like twist.
It´s a non oriented surface like in the attachement.
My problem is, since it´s a sphere, the eversion of the cut surface of the twist.
Can anyone help me out on how to realize this twist in NX 11 ?

 

[Toost]

NX (i.e Parasolids) will probably not allow you to create this as a solid body. It will allow you to create this as a sheet body.
It would fail on the solid modeler logic that one side of the same surface "is the outside of the volume and the other is inwards".
As said, i doubt it, but you never know.

A sphere in NX is a "analytic surface", - it cannot deform to a different shape . This means that the spherical shape of that thing can be "part of a sphere" , but the holes and that transition must be separate faces.

Another question is "how much sperical" should that transition be ?
Should the transition edges/ faces touch a theoretical sphere ?


( What is the purpose of this exercise ? )

Regards,
Tomas

 

[Toost]

A tip on issues like this,
print that image you supplied, then using a pen, try to divide the difficult shape into four sided areas. - All CAD surfaces are four sided. As large as possible but also as simple as possible, each area/ surface should not "have more shape than an S-shape".
When you have a plan, start NX.

Regards,
Tomas

 

[James93]

Thanks for your answers.

Ok so if i want to create the whole sphere with twist as a whole it is impossible, but what if i create the twist and add it to a sphere afterwards , that should be possible, shouldn´t it ?
I had the idea to create four splines for each corner of the cut surface of the twist.
My problem now is that i cannot make an extrusion out of those splines, is there a possibility ?

 

[Toost]

hm, i couldn't keep my fingers off this...
It is possible to create the sphere as one feature and the twist as ( several) features. - Trying to make the twist as one single feature might work but might "leave too much to the System to interpolate in one go". - You might end up with edges on the wrong place etc etc. designing each face/surface one at a time allows for detail attendance.
NX also allows to unite the twist to the sphere. ( i was wrong earlier, this model does not have faces which are both inside and outside) In the attached example the last sew is dependent on extracted faces which NX doesn't like to unite back, the twist is a separate body. ( if the sew

Attached is a quick sample.

Regards,
Tomas

 

[Toost]

seems there is something wrong with the file upload currently.
will , if i remember to , upload tomorrow.


/ Tomas

 

[Toost]

Here we go
As said , a simple variant.
/ Tomas

 

[James93]

Ok first of all i apologize for not answering more quickly, i had alot of other projects to finish, and second of all i´m very impressed with your result.
I find it very interesting you used the square as a cut surface for the twist in the middle, and i played around with various sizes and shapes to get the result i wanted.
So in conclusion, i thank you very much for your help i learned alot from you and i find your way of approach simple yet smart!

 

[Toost]

The surfaces had a tendency to become ugly / self intersecting due to the twist, so i added the square to dictate the shape in the middle.

Regards,
Tomas