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ZeroLengthCurve  
#1 Posted : Friday, December 18, 2009 8:25:09 PM(UTC)
ZeroLengthCurve

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I am being frustrated by my incapability to extract a single-entity surface from a 1696 pieces surface.


Here is my process that is not working:


1. Selected an empty layer to be target of anticipated kept solid
2. Selected "Subtract Solid" tool
3. Selected solid to subtract from
4. In Select Mask, deliberately selected the color corresponding ONLY to the joined surfaces surface
5. noticed "Ctrl" to retain subtracted part

6. clicked on the joined surfaces surface

7. Checked the target layer for new creation, and NO OBJECT IS THERE; no new objects created ANYWHERE
8. Checked undo, and undo indicates recent undoable item with: "undo subtract solid1"
9. Inspected the Concept Explorer; could not find the kept subtracted part

Where is the retained subtracted part?


This seems so simple to me: Use one or more surfaces, single or joined that behave as one, and use for reverse-Boolean-creating a new surface so i can discard the highly undesirable, 1696+counts joined-surfaces-surface. "Undesirable" is an absolute understatement. I am coming to the mind that the fewer extraneous parts in the model the better. I don't know that i should have to resort to Rhino or some other tool to create outside of ViaCAD Pro a part or surface that i can see in VC Pro and not manipulate in ViaCAD Pro. I am starting to feel that if i can SEE it i should be able to do fundamental things with it.

If i can see it in ViaCAD, and if i can select it, why cannot i convert it into a simplified surface down to 2 or 3 vice 1696 faces? Upon simplifying the object, i get:

Attempt to simply the part.
Simplify Results

! Examined 1696 faces.
Converted 0 NURBS faces to 0 analytics.
OK.


I tried the "offset surface" tool. It provided nothing i expected.

What am i doing wrong (other than having a misinformed expectation)?


Please note: this problem i am having is an extension or another take on a previous problem. As i understood from the forum reply, ViaCAD's specialty is not in breaking down mesh surfaces from other tools into something that can be used for cutting surfaces in ViaCAD, or something to that effect.

But, this is a fundamental, crucial, undeniable impact on what i need to do. Ultimately, i may have to go back to the original mesh, break it down again, then every-so-many-feet of multiple surfaces join those until i get through all ~500 feet of surface that is too curvy and complex to sweep from the bottom centerline up to the 1-foot waterline.

Thanks for any input!

UserPostedImageAs for the attached .vcp files, the 1.32 mb file has the joined surfaces as one join made of the 1696 surfaces. the -a file, which is 375.9 kb, has 4 surfaces, color-coded to help anyone wishing to play with it not have to guess at breakdown points i might need or want.

Please, try not to supply me surfaces made OUTSIDE of VCP or VC 2D/3D. I need to learn or be told how to do this IN VCP.

Also, I tried in Shark Beta 7, build 921, and cannot yet determine if what i am attempting is even possible there, either. But, in both VCP 6 and Shark Beta 7, i CAN subtract the surface from the solid. What i tried to do but cannot figure out is how to reverse Boolean the solid, or keep the cut out piece and discard the larger portion.

Thanks!

UserPostedImage
File Attachment(s):
mesh-surf-subtraction-tests-a.vcp (376kb) downloaded 5 time(s).
mesh-surf-subtraction-tests.vcp (1,355kb) downloaded 5 time(s).

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ZeroLengthCurve  
#2 Posted : Friday, December 18, 2009 8:42:02 PM(UTC)
ZeroLengthCurve

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Attached two jpg files to facilitate preview of what is in the vcp files.

I am using VC Pro, build 852.
ZeroLengthCurve attached the following image(s):
01-surf-and-solid.jpg (29kb) downloaded 5 time(s).
02-surf-and-solid.jpg (18kb) downloaded 5 time(s).

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ZeroLengthCurve  
#3 Posted : Friday, December 18, 2009 9:08:24 PM(UTC)
ZeroLengthCurve

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I am wondering whether this would work:

Boolean another solid tube against the one with the cutout. I already know that using the menu:verify interferences tool DOES NOT work as i anticipated, maybe because of the joined surfaces that originated from meshes.
Steve.M  
#4 Posted : Friday, December 18, 2009 9:16:01 PM(UTC)
Steve.M

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Originally Posted by: ZeroLengthCurve Go to Quoted Post
Where is the retained subtracted part?


It is the part you are using to subtract that is kept, not the part that is being removed by the subtraction, so no new part is actually created.

A simple example is to have 2 cubes overlapping, subtract one from the other with the ctrl key pressed to retain, you still have the 2 cubes, it is just one of them is now missing the part of the overlap.

It would only be on an intersection, that a new part is created.
ZeroLengthCurve  
#5 Posted : Sunday, December 20, 2009 5:23:39 PM(UTC)
ZeroLengthCurve

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The wavy strip of Punch blue geometry (in image 03) is part of what i am after, if only i could keep VCP from separating it from the "selected" surrounding geometry (in imge 03) that is sticking around. Somehow, it got separated from the other to surface joins.

I guess i was hoping that by first subtracting and then surrounding the subtracted volume i could generate some sort of "gapfiller" or capping. It would be like scooping out some matter from a solid, filling the void with material, letting it harden, then trimming off the unneded edges-except digitally. Well, like taking a mould of a shoeprint.

Anyway, do you or does anyone out there have any ideas for me. I can clearly SEE only the solid i wish i could have, but when i click it, VCP then displays the rest of the object, the surface of the solid that was involved in the subtraction process.
ZeroLengthCurve attached the following image(s):
03-surf-and-solid.jpg (14kb) downloaded 5 time(s).
04-surf-and-solid.jpg (38kb) downloaded 5 time(s).

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ZeroLengthCurve  
#6 Posted : Sunday, December 20, 2009 6:26:54 PM(UTC)
ZeroLengthCurve

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It would also seem that there is another error/misunderstanding on my part: For some time, I mistook the ISO lines and their coincidental lining up with the locations of the surfaces to mean that if i drilled through the surface later on that i'd end up with innumerable surfaces to rejoin.

Nicely/fortunately, i turned on transparency while playing around. I noticed the ISO lines disappeared and then i erroneously (reaching) hoped to find that i somewhere along the way created a single surface out of the joined surface. But, backtracking my steps i realized i did no such thing.

I have to go now, but i want to try this in Shark 921 to see whether it repeats...
But, after holing some geometry, i found i could not (easily) cover fill or create a surface in the perimeter of ellipse lines. And, when i joined the ellipses, the lines "moved". The final join jinked/kinked the lines. I am sure that superimposing this surface on one saved from an intersection subtraction would not be the same shape or volume or contact the same original coordinates.

However, i decided to remove material by using a cylinder. I subtracted from the surface the cylinder's intersecting material (using the subtract tool) and pleasantly realized the joined surface is not decomposing or disintegrating to hundreds of surfaces.

Next, i broke down the surface to curves (vice surfaces and meshes) and created "panels" which could serve as local areas of plating to simulate or to be areas where appendages (fins, other things) or tunnels/ducts could penetrate the hull.

However, i found that when i subtract some surface, i cannot retain the disk. It might be useful for determining how much weight is removed (after thickening of the plating) compared to pre-removal. Not that terribly important since i can thicken first, get the weight, then sub the material, and check the weight again. A little extra work, but is OK.

Somewhere in this, i might temporarily be able to bypass my earlier problem of getting those 4 joined surfaces trimmed to coincide with the deck edge, more for tidiness, since in the real world just jagged edges would be ground down and smoothed prior to welding.


----

The "what if i..." files are related to trying to fill the hole left after using a cylinder to remove material from the surface. It seems that trying to refill the hole ends up producing a surface made of the ellipse's curves that when joined are not in the same geometry as the curves created by the holing... see other related thread
File Attachment(s):
hole-fill problem.vcp (16kb) downloaded 5 time(s).
what if i want to fill the ellipse.vcp (20kb) downloaded 5 time(s).
ZeroLengthCurve attached the following image(s):
06-hole-fill problem.jpg (18kb) downloaded 5 time(s).
07-what if i wanted to fill the ellipse.jpg (23kb) downloaded 5 time(s).

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blowlamp  
#7 Posted : Monday, December 21, 2009 3:26:56 AM(UTC)
blowlamp

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Joined: 6/28/2008(UTC)
Posts: 648

Hi ZLC.
Would what I was asking for in this thread http://forum.punchcad.com/showthread.php?t=2636 be of any help to you, because I would find it most useful for certain jobs? I realise it isn't the main request in your post - just wondered if you would find it helpful.


Martin.

**Merry Christmas everyone**
ZeroLengthCurve  
#8 Posted : Monday, December 21, 2009 1:49:02 PM(UTC)
ZeroLengthCurve

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I think it will be. I experienced what you wrote in your November thread. As i was experiencing my event, i thought i was sooooo close to getting what i wanted, but then something confused me into disarray. I need to work back through my steps and try to arrive at something.
zumer  
#9 Posted : Saturday, December 26, 2009 8:47:56 AM(UTC)
zumer

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You're pushing the proverbial uphill if you expect ACIS to offset or thicken a mesh because of the complexity of junctions where more than three faces share a vertex. But, if you do a bit of slicing and dicing of your meshes into less complex sections, you might have more chance of success. I did use TurboCAD for this, purely because I get continual ACIS access violation messages with your files in FX beta 922, all I could do with it was export as .sat.
zumer attached the following image(s):
sliced mesh surface offset.PNG (39kb) downloaded 5 time(s).

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