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Loft with a Hole in the Section

Experimenter
Experimenter

Does anyone know of a way to create a loft on a set of curves including a hole?

Attached is an image of the curves I'm working with. They are irregular shapes. I've been messing with some of the surface features (mainly loft) for a while and I can't figure out if it's possible to include the hole in a single loft-like operation. Can I select all of the bottom curves as the starting point, then select all of the top curves to be the end point some way? Does a hole basically screw up the boundary conditions and make the solution impossible?

I can loft the outer curve and inner curve separately then subtract the hole, but I'm looking for a more concise solution.

Thanks!

8 REPLIES

Re: Loft with a Hole in the Section

Siemens Phenom Siemens Phenom
Siemens Phenom

Like I already asked in another forum, what exactly are you attempting to model?  It looks like a section of a tree-trunk, like those tables made from a slice of Cypress wood:

 

football-coffee-table-shaped-tablesfootball-tables-herringbone-rh-timber-pinterest-wood-for-top-search.jpg

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA

Re: Loft with a Hole in the Section

Experimenter
Experimenter

John, it's a leg muscle, the hole is where the model of the bone will be incorporated. There are thousands of these cross sections for the whole leg, I only included two of them to get the idea across. Since there are so many I was looking towards automating the process, which is why I wanted to see if the operation could be simplified.

Re: Loft with a Hole in the Section

Genius
Genius

just for curious, how do you plan to align all those (many) sections, being so irregular ?

The hole seems to me the least of your problems, I would be content just to get an

acceptable loft with the outer curves, to start with.

Re: Loft with a Hole in the Section

Siemens Legend Siemens Legend
Siemens Legend
Hi @Tugummi
Is it possible to share one section that fails on the extrude? There maybe another way to do this but we would need the problem section to test. Or is there an IR/PR number against this?
Regards
Paul

Re: Loft with a Hole in the Section

Legend
Legend

Depending on the purpose for your model, I think your approach is too simplistic.

 

Years ago, a colleague needed to model the statue of liberty in I-Deas for a lighting study. He quickly found out that, although it was an intuitive approach,  one Loft (Through Curves) would not work, because different parts of the statue started and ended in different places. He found that he needed to model the arms, the folds of fabric, etc as discrete features and then join them.

 

I think your leg model is similar. The leg consists of multiple discrete things. There are multiple muscles that begin and end in different places. But the bone you mention continues past where the muscle is attached. Another way of saying this is what others have questioned- your sections are very irregular, and it will be hard to match them up. The reason it will be hard to match them up is based on the physical reality that they don't match up. The irregularities are a result of the fact that the section includes different discrete muscles, etc.

 

 

 

 

Re: Loft with a Hole in the Section

Genius
Genius

also, one cannot help wondering whether a NURBS reverse eng. of such a complex part is needed at all.

With today's techniques much can be done with tesselated models, including modeling, milling, etc.

But I suppose the OP can explain this.

Re: Loft with a Hole in the Section

Valued Contributor
Valued Contributor
A weird way of doing it.... If you make a wrap of all those curve with a circular array of cutting plane at the center... adding datum plane would give you a more precise result and you could select all your section at once with that hole in the middle. probably need's some edge blend after to get it smooth... If you reuse the same function every time, you could only change the section selection and not the datum plane's and save a lot of time!

Re: Loft with a Hole in the Section

Siemens Legend Siemens Legend
Siemens Legend

Hi Tugummi,

 

Without fully understanding the complexity of your case as it is only an image its difficult to guide you. I assume that, since as you are asking, this is something that you frequently do. If so I suggest lookin into UDF's and Reusable objects as this is a way for you to standardize and somewhat automate your workflow and simply create your own feature based on standard NX functionallity. The attached video shows an example of Reusable Object.

 

Best Regards

Fred

(view in My Videos)