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Free form modeling

Free form modeling

Free form modeling

(OP)
Dear all,

i'm having trouble to create a free form model, not sure if i should use the "Trough curve mesh", "ruled" or something else. I can't create a nice transition between the surfaces of the blend and the straight part.

What am i doing wrong?

Thanks in advance.

Best regards,

Michäël.

NX4.0.4.2 MP10 / TCE 9.1.3.8_build_0711 / NX6.0.2.8

Belgium

RE: Free form modeling

"Trough curve mesh", can make C1 or C2 continuity to side surfaces. So your transitions wil be verry smooth.

Dont use "rule surfaces" for smooth transitions.

RE: Free form modeling

I don't think you did find the solution if you perform an examine geometry you'll see why.

On the other hand the attached file suggests a close approximation to what you wanted.

The problem is that anything coming to a point pretty much risks self intersection of consistency errors by definition.  

Best Regards

Hudson

www.jamb.com.au

Nil Desperandum illegitimi non carborundum

RE: Free form modeling

(OP)
Hudson,

you're correct. I did not examine the geometry of my part.  After i prefromed one, it found self-intersecting geometries/faces. But it did not stated where, or what i should do to correct this errors. Also looking in the z-axis at our model, i see a weird bubble on top of the curve mesh(12) its like an s-shaped sheet, does this have to do with the G1 continuity of the feature?

Thanks for helping out.

Best regards,

Michäël.

NX4.0.4.2 MP10 / TCE 9.1.3.8_build_0711 / NX6.0.2.8

Belgium

RE: Free form modeling

Michäël,

As I mentioned mesh surfaces coming to a point are frequently uncontrolled at the pointy end. Perhaps if you have a look at the surface poles then you'll get some idea of what might be happening. If I was able to do better with a curve mesh surface I might attempt it. Instead what I have shown is probably about as close as you'll get to creating useful geometry for the particular case that you're trying to work with.

Best Regards

Hudson

www.jamb.com.au

Nil Desperandum illegitimi non carborundum

RE: Free form modeling

Mike,

I think that it may have been that in NX-6 the selection dialog was defaulting to include a point along a curve where you specifically need to turn that off to ensue you're selecting end points. did both sides at once on both occasions.

Also in looking at your query I first thought to blend the flip side. Here we can only manage blends up to about 0.3 in size because exceeding the dimension of the step creates a problem with attaching the blend.

Best Regards

Hudson

www.jamb.com.au

Nil Desperandum illegitimi non carborundum

RE: Free form modeling

I had a shot at this, unfortunately I do not have access to NX, this was done in SolidWorks but they both have the same Parasolid underpinnings so I guess it's all good.

The patch layout I ended up with is kind of odd, but it looks kind of good, and anything beats those 3-sided horror surfaces soon to be featured in SAW 6...

Just trying to help out :)

CSWP-Surf

RE: Free form modeling

Kevin,

Interesting concept. I'd use a slightly different construction, but it does open up a route to having a larger radius on the opposite side. It does not follow the intent of the original question, but who's to say that we always get the question right!

I've made a couple of notable corrections to the original earlier model that I built upon since I had not noticed a neglected continuity on the flip side that came to me with that file. Don't ask and don't tell and all's well that ends well I guess wink

Best Regards

Hudson

www.jamb.com.au

Nil Desperandum illegitimi non carborundum

RE: Free form modeling

Hudson,

Excellent patch layout there.
Why didn't I think of that? ;)

CSWP-Surf

RE: Free form modeling

One thing I've always wondered, do solid models and surface models care about being edge looped?

I attached another parasolid with a barage of split lines, the idea is to explicitly create four sided surfaces.

I don't think this has any value for NURBS, but I'm not sure, so I thought I'd ask :)

CSWP-Surf

RE: Free form modeling

Kevin,

To tell you the truth the terminology edge looping is hardly if ever used within the NX community. You could use the divide face function to achieve a similar thing, but most NX users would use associative projected curves or sections to achieve the same effect.

These internal edges would in most cases be unwanted because they may show up on drawings. You can manipulate settings to make them disappear but it distinguishes using tangency as the delimiter and setting the drawing views not to have internal tangent edges means tangent corner blends might also disappear causing the object to look under defined. You do have the ability to also use manual "view dependant" edits but that creates unwanted extra work.  

Best Regards

Hudson

www.jamb.com.au

Nil Desperandum illegitimi non carborundum

RE: Free form modeling

Hi all

Only just seen your thread (been on my hols) and thought I would have a go at it. Anyway my model is attached and is nice and associative, change the blend etc and everything updates as you would expect. What do you think?

Best regards

Simon NX4.0.4.2 MP10 - TCEng 9.1.3.6.c - (NX6.0.3.6 MP2 native)

www.jcb.com

Life shouldn't be measured by the number of breaths you take, but by the number of times when it's taken away...

RE: Free form modeling

(OP)
Simon,

this is looking good, a very nice model. I have one questions though, why do you use the extrude (19)? The trough curve meshes only uses the bridge curves?

But thanks again,

(should start a 'Well constructed cad models' - thread again) This type of modeling is fun.

  

Best regards,

Michäël.

NX4.0.4.2 MP10 / TCE 9.1.3.8_build_0711 / NX6.0.2.8 / NX7.0.0.9

Belgium

RE: Free form modeling

Micky

I used the extrude 19 to give me 2 control sufaces for the cross strings of my through curves mesh otherwise when I mirrored the sewn body, it might have given me a dodgy join to the surface. winky smile

just posted another model on the well constructed front!
 

Best regards

Simon NX4.0.4.2 MP10 - TCEng 9.1.3.6.c - (NX6.0.3.6 MP2 native)

www.jcb.com

Life shouldn't be measured by the number of breaths you take, but by the number of times when it's taken away...

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