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i do not understand blending (#4236)
Rank: Member
Joined: 2/22/2008(UTC) Posts: 70
Hallo,
it happens so often, so i want to ask, what i'm doing wrong.
Sometimes, in my case very often, the blendingtool destroys my whole modell.
please see the picture. the upload for the original ViaCad Pro 7 file failed.
maybe about dropbox ?
http://dl.dropbox.com/u/7165382/Mantelring_forum.vcp or
http://dl.dropbox.com/u/7165382/Mantelring.vcp.zip awieneke attached the following image(s):
want to blend.jpg
(109kb) downloaded 5 time(s). happens after blend.jpg
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Joined: 9/12/2009(UTC)
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Sounds like a video card problem. Try this. After blending, change the resolution. I have sometimes had the model reappear this way as long as when you highlight something the entire profile of the part is there.
FX 7-FXPro14-1650
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Rank: Member
Joined: 2/22/2008(UTC) Posts: 70
Originally Posted by: rockyroad_us Sounds like a video card problem. Try this. After blending, change the resolution. I have sometimes had the model reappear this way as long as when you highlight something the entire profile of the part is there.
mmmh not really,
i can export this funny piece of anything.
it becomes an stl file
awieneke attached the following image(s):
Bildschirmfoto 2012-03-05 um 18.26.25.jpg
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Confirmed. Not sure what is going on with your model. I'm guessing the hollowed out part of the inside of the ring causes this disappearance. I've done rings in the past but I have taken a surface approach to make the surfaces and then make it into a solid. I have better control of the profile when using curve profiles. Is the hollow required around the ring hole?
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What's happened (I think, anyways) is that where the outer body of the ring intersects with the inner ring isn't well enough defined. I don't think that it's the way you made it, I think that it's a shortcoming of the ACIS kernel, or maybe just the level of precision. I've made an experiment based on that theory, and the file I've uploaded has a couple of small filler blocks. Add them to the ring and try the blend again. It should work, and will give you a direction to explore.
With your file, the kernel tries to establish a blend, but in the areas I've circled in yellow on this picture, there's no substance, solid or surface, behind the blend, and the kernel doesn't have a routine to cover instances like that, so it crashes.
File Attachment(s):
Mantelring_forum1.vc3
(19kb) downloaded 5 time(s). zumer attached the following image(s):
successful blend.jpg
(30kb) downloaded 5 time(s). why no blend.PNG
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Rank: Senior Member
Joined: 2/19/2007(UTC) Posts: 186
It's because your ring is hollow and the edge that you want to blend doesn't make a good join with the outer shell. I suggest that you need a different approach, and should make the shell solid up to the line in the image, before you insert a tube for the finger hole.
billbedford attached the following image(s):
Mantelring_forum.vcp.jpg
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Rank: Member
Joined: 2/22/2008(UTC) Posts: 70
thank you to all of you. i build the ring a little bit different and it is fine now. sure, i can build it different. but i'm sometimes a little bit lazy ;-) :: rockyroad_us: i build rings often with surfaces but in this case i tried to build it up with the loftnurbes. i thought it is faster 'for me' 'zumer': how did you build the filler block such fast ? and your answer, that the kernel can not manage this, helps me, because it is not really my fault. Thank you ! my solution was to make the shell more thick, so the lower part is solid. after this i had some problems with the blending for the outside. The idea is to let it print and cast in silver and it should have less weight. i do the blending outside by hand, after casting. anyway, i was wondering, because viacad's advertising is, it makes perfect blendings all the time. so i learned a lot and hope that i'm not running so often into this problem again, because i had it very much in the past.
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I put a cut section through the ring and extruded a solid from the profile of the cavity. There're lots of ways, though. Draw a rough profile that encloses the cavity and extrude, or cover-surface it and thicken. I think it'd be elegant to make the finger-tube outer profile elliptical, or with wings on the circular profile, so it'll block off the cavity automatically.
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Joined: 3/6/2012(UTC) Posts: 16
You might try selecting a face as the fillet geometry also, to see if you can get results...
[ATTACH]4300[/ATTACH]
BurrMan attached the following image(s):
face_fillet.jpg
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Rank: Junior Member
Joined: 3/6/2012(UTC) Posts: 16
I would say it is not an ACIS filleter limitation. It has to do with a badly trimmed surface inside the ring cutout. It appears to me to be a result of having the model "shelled", then running the cutout of the ring, which did an intersection of the inner and outer shell, right at the seam point of the cutout circle.
So here is a picture where I deleted the outer surface.
[ATTACH]4301[/ATTACH]
You'll see a fragment edge protrude from the tip of the top surface to the lower one (This should have been a clean cut). It emulates from the inner cutout circles seam edge.
The filleter is having an issue with "traveling down and around this entire area" with it's auto chain mechanism. If you select the opposing edge from the one you specify in the original screenshot, then it will also fillet, like a face fillet, because the chain selection will bypass this malformed edge and the filleter can consume the entire area.
These types of modeling defects can be avoided by paying attention to keep "seam edges" out of critical areas of booleans and trims and such.
FYI
BurrMan attached the following image(s):
frag_edge.jpg
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Rank: Junior Member
Joined: 3/6/2012(UTC) Posts: 16
I think I was wrong regarding the badly trimmed surface, as it was a result of translation I did to look at the model in other packages, but the area in question is still the culprit.
The model has 2 surfaces that are constructed "Self intersecting".
[ATTACH]4302[/ATTACH]
The 2 surfaces with the red x intersect where the green circle is.
Here are the 2 surfaces shown in another package with seperate colors that show the intersection area. (I wish I could show this with ViaCad, but I am still too green to get it done)
[ATTACH]4303[/ATTACH]
This type of surface intersection within a volume will create various problens with further booleans and fillets, that require edge boundry calculations.
BurrMan attached the following image(s):
surface_intersection.jpg
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Joined: 3/6/2012(UTC) Posts: 16
Ok, so I finally figured out how to unstitch the model properly with ViaCad, using "change object type" convert to surfaces (One of Tims videos) then I could hide that outer surface and ViaCad would show the intersecting surfaces in that area well... The fix would be that the fingerhole size needs to shrink, the shell needs to be smaller value, or the outer size of the ring needs to be larger, to allow for volume in that area.
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Joined: 2/22/2008(UTC) Posts: 70
i'm still wondering.
all of you have very good ideas and i learned a lot.
i played a little around and it is working now. I used the opposite side and the blending works.
maybe i have changed something with the lower part, because after cutting it looks to me as a solid.
the blending for the 'ringsize' works.
The blending for the buttom part not.
It is a good idea to cut the model for looking inside, i had it no in my mind. Thank you.
is there a more simple way to build a ring like this ? We call it 'mantelring' in german. If i cut the ringsize later, i have no simple way to make the tube for the ringsize. and i do not want that there are edges on the finger and that it looks hollow.
awieneke attached the following image(s):
blend is now ok.jpg
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Rank: Member
Joined: 2/22/2008(UTC) Posts: 70
Thank you all,
befor i finish the ring, take a look how the casted ring looks in silver.
nice blending ;)
[ATTACH]4341[/ATTACH]
awieneke attached the following image(s):
blending.jpg
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Joined: 11/25/2009(UTC)
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How did you cast your ring? Lost wax casting! (wax 3D printing)?
METEORE DESIGN / KEKO Stand Jean-Francois Jacques, Industrial Designer SharkCad Pro V14 B1653 Platform macOS 14 Sonoma
Rank: Member
Joined: 2/22/2008(UTC) Posts: 70
Originally Posted by: Jean-Francois Jacques How did you cast your ring? Lost wax casting! (wax 3D printing)?
Hallo Jean-Francois ,
in this case i play around with shapeways. They print it in wax and cast it in silver.
I had to to clean a little the surfaces.
Normally i send it to a wax 3D printerservice and after to a casting company.
they can do it in also in gold and platin.
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Thanks Andreas, I know shapeways, is offer very interesting services.
METEORE DESIGN / KEKO Stand Jean-Francois Jacques, Industrial Designer SharkCad Pro V14 B1653 Platform macOS 14 Sonoma
Rank: Member
Joined: 2/22/2008(UTC) Posts: 70
so,
now the ring is finish.
Thank you to all of you, for helping me to make this model with ViaCad.
The ring is filled with concrete.
[ATTACH]4391[/ATTACH]
awieneke attached the following image(s):
betonring_1.jpg
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Rank: Senior Member
Joined: 2/26/2007(UTC) Posts: 2,156
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Danke, merci, Thank you ;-)
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i do not understand blending (#4236)
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