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TobiasLarsson12-Amethyst
12-Amethyst
April 8, 2016
Question

aproximate copy of SURFACES?

  • April 8, 2016
  • 5 replies
  • 7184 views

I asked this question on mcadcentral recently, but i haven´t got a solution for it yet so here we go:


Is there any way you can copy a couple of quilts to get a single quilt surface? (like when you copy some curves, and pick approximate and get just one curve) .

I found that you can make a copy of a couple of surfaces, use offset and under "options- special handling" set the quilts to be apporximate and get a result that is "one single surface". The problem there is that i have to set a value for the offset , it cant be "zero" (and also that it behaves a little funny sometimes) .

So, is there a way to get an approximate surf? Or just a way to connect quilts to be one single quilt.

//Tobias

Ps, the reason i want to do this is because when i´m patterning something that goes over a few quilts, it sometimes becomes very unstable and may fail if the quilts changes shape...


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5 replies

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TomD.inPDX17-Peridot
17-Peridot
April 8, 2016

Default offsets at zero work better than anything else. Not sure why you cannot use zero.

Older Creo 2 releases had some serious patterning problems.  Knowing that, I am still on M040.

Look up Copy Geometry...

...or resort to importing an IGES saved version.

Everything PTC is known as "touchy"... but never unstable

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TobiasLarsson12-AmethystAuthor
12-Amethyst
April 8, 2016

Thanks for your answer, but a default offset at zero give me nothing else than a regular copy so that won´t work since I want to get a single patch surf. ( and i could live with the fact thats its an aporoximate surf as long as it dont deviate to much from the original) Regarding copy geometry, since it´s in the same modell i want my single patch surf, i dont see how that can be used , and exporting and importing a iges to the same model sounds like a not preferable workaround , especially when you want to update your geometry.

//Tobias

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svlaminck10-Marble
10-Marble
April 8, 2016

Seems like offset 0 remains the same surface.

Workaround could be:  offset +1mm and the "offset approcimate" it back -1mm

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TobiasLarsson12-AmethystAuthor
12-Amethyst
April 8, 2016

well, actually No. You cant set zero as a value when offsetting a surf if you set the surfs to be aproximate (special handling). If you skip this, you can set it to Zero, but then it´s just a regular copy. The feature wont fail, but it will also NOT make an aprox surf , it will actually not make a surf at all.

And Yes , the workaround could be to offset it to a value, and then offset it back to the original position . The thing here is that when i do that in a complex surf , the result is too far off the original surf. ( Would be nice to be able to set a value for the deviation too, but first lets figure out how to create the aproximate surf!)

And hey, i just tried to get the result using copy or offset. If anyone have a different approach to create an aprox surf, I would be grateful to hear about it!

//Tobias

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svlaminck10-Marble
10-Marble
April 8, 2016

May i ask why you need the surface "approximate" or whitout tangential lines?

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TobiasLarsson12-AmethystAuthor
12-Amethyst
April 12, 2016

Any more suggestions?

//Tobias

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DeanLong1-Visitor
1-Visitor
April 12, 2016

Tobias,

Will you be able to "replace" (Old School Patch) the offending surfaces with a new one? There is a technique that I use for this situation when the patterns fail.

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TobiasLarsson12-AmethystAuthor
12-Amethyst
April 12, 2016

Hi Dean!

Well, the thing is that "i need a new surface where i can place my pattern " , and yes replace ( i do remember old school patch 😉 ) could work just fine , but the thing is that the surf used for replacing has to be modelled and i want to skip that step!

I dont want to "model" a new surface for the pattern, i would like to use the surfaces already created (in some way...) and then get the same geometry (or very close to that..) but with (at least...) minimal patches or intersections on it.

It works pretty good using the offset command and special handling of all surfs when offsetting to a minimal value (like 0.1mm) and use that surf for placing the geometry to be patterned. If there is another way to create the "singlepatch surf" i would be great, then i can the perhaps even use the "replace" for the new surf, but thats a bonus..

( I bet creo can do this mathematically , like when you model something in freestyle , creo can convert this to a 4 sided surfaces geometry. I think there got to be a way to get creo to take my already created geometry and convert it to a similar geometry but placing new 4 sided surfaces in the best way to get a superb and smooth surface. Atleast maybe in the future )

//Tobias

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rrich-21-Visitor
1-Visitor
April 12, 2016

I believe you can do this by copying the surfaces and using merge or possibly group.  However I would need to see the model and what you are trying to do in order to give you a definitive answer.

Ron

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TobiasLarsson12-AmethystAuthor
12-Amethyst
April 14, 2016

Hi ron,

Please elaborate your thoughts . The thing is that i want to get a single patch surf out of already created parametric surfaces. The surfaces thats alreday crated is made of several sweeps (old scholl "variable section sweep), some boundaryblends, and/or isdx surfs thats merged together in to one single quilt, but then i want to get rid of, or atleast cloce to, the patchlines. I cant see how grouping the features could help, but maybe i´m missing something!

//Tobias

bbrejcha
bbrejcha15-Moonstone
15-Moonstone
April 16, 2016

just use aprox copy composite curve over the projected curves across the compound surfaces.  Hi Dean and Tobias!

Bart Brejcha

Design-engine.com

Bart Brejecha designengine.com
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TobiasLarsson12-AmethystAuthor
12-Amethyst
April 18, 2016

Hey Bart!

All good?

Well, i do know how to build high end surfaces using compositecurves, although i prefer higher degree isdx curves over that since i fell i get more controll over the shape. But, as you know, when creating complex geometry you need to build several surfaces, and what i´m looking for is a way to do the same thing as you describe for curves, but instead on surfaces. I.o.w, copy several surfaces and make them in to one single patch surf. it´s possbile using offset- special handling- aproximate, but not on zero value.

//Tobias

bbrejcha
bbrejcha15-Moonstone
15-Moonstone
April 18, 2016

Tobias-

we are getting in Creo 4.0 the G3 functionality.  So exciting since we have higher order curves.  So excited!    I have a funny story for you concerning G3 and 7 degree curves w/ respect to Creo.  Ill email you. 

Bart Brejcha

Design-engine.com

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Bart Brejecha designengine.com
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