nurbs modelling

# 1 07-04-2010 , 11:27 AM

Registered User
Join Date: Mar 2009

Location: India

Posts: 145

Hello everyone

I am trying to model a basic ball point pen using nurbs. Three fourth of the pen has a hexagonal shape and the rest of the pen body is cylindrical. How do i merge both these shapes. even rebuilding the curves to match each others UV parameters is not helping.

https://img15.imageshack.us/i/picture....th.jpg%5B/IMG

Also attaching a picture. link above

please help

Mahesh

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# 2 07-04-2010 , 01:05 PM

The Nurb Herd
Join Date: Oct 2007

Location: London

Posts: 2,381

nurbs dont need to be merged. maintain the tangency and it will render as one piece... i believe.

unless its some sort of project for uni or something then, why not just stop using nurbs. convert it to polygons. sounds like you don't need to learn anymore about nurbs other than when to quit. user added image

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# 3 07-04-2010 , 02:28 PM

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Join Date: Mar 2009

Location: India

Posts: 145

Hammer.horror

yes, you are right. Its for the univ.

i am also aware that most of the work is carried out in polygon. Its just that we are being taught about nurbs modelling at present.

Anyway i really appreciate your help

regards,
mahesh

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# 4 08-04-2010 , 05:07 AM

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Join Date: Jan 2004

Location: Michigan, USA

Posts: 2,998

Sigh,

So many people just refuse to stop ragging on nurbs.

What you want to do is simple.

I am going to describe how to do it with degree 3 curves in u and you will end up with degree 1 curves in v. Getting degree 3 in both u and v is easy but trying to describe in with text is more trouble then I feel like going into. 3x1 will look fine.

1. create a nurbs circle and in the channel box set the number of spans to 18

2. duplicate this curve and pull it the distance to the top of the pen

3. take the first circle and grab cv's in groups of three and scale them uniformly together to form the hex shape

4. now duplicate this curve and pull it to the top of the hex shaped part of the pen

5. go back to the circle shaped curve and scale is just smaller then the hex shaped curve

6. now duplicate the curve from step five and move it just above the hex shaped curve at the top of the pen.

7. now you have 4 curves you could select them all in order from the bottom to the top and select surface>loft (you will get something that looks really scary, but do not worry changing from cubic to linear will fix it) and then in the channel box change from cubic to linear

done.

If you want all cubic surfaces in both u and v. Create three separate lofts. Then you can attach the three surfaces and you will have to add additional isoparms to keep the transitions tight. But for the most part I am sure the result you get following steps 1 to 7 will be fine.

"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675

Last edited by ctbram; 08-04-2010 at 07:28 AM.

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# 5 08-04-2010 , 06:41 AM

Registered User
Join Date: Mar 2009

Location: India

Posts: 145

Thank you so much ctbram.

I tried as per your suggestion and it worked. I am attaching picture of the same.

https://img85.imageshack.us/i/penz.jpg/

Thanks again for giving me your valuable time.

:bow:

Regards,

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# 6 08-04-2010 , 11:26 PM

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Join Date: Jan 2004

Location: Michigan, USA

Posts: 2,998

Glad it worked.

Back when Maya 3 was out and desktop computers did not have the CPU performance and memory capacity of Cray super computers NURBs was the ONLY way to model.

I am not gonna kid you. Maya's NURBs tools are full of problems, because they appear to be watered down versions of what were part of a more powerful professional surfacing application studiotools (now autodesk automotive).

But they are still very powerful, you just have to work within their limitations.

"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675

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