boolean union strangeness

Next
 From:  twofoot
7945.1 
See attached file. The snapshot within Moi shows odd geometry, but the STL file is clean and has no artifacts.

It is a tricky shape due to the tapers and cutout sections. Scale is MM.

Any thoughts? All of my layers are included as hidden objects. I would happily redraw the object in a different manner if i could make fillets easily and have a watertight solid. Sorry if I am being vague, but I've been up since 4am with the baby. LOL

Thanks

Chris

Image Attachments:
Size: 742.6 KB, Downloaded: 32 times, Dimensions: 1330x748px
Size: 72.5 KB, Downloaded: 30 times, Dimensions: 1034x801px
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  Michael Gibson
7945.2 In reply to 7945.1 
Hi Chris, it looks like there are a couple of areas that have damaged trimming boundaries, like there's something wrong here:



So that and another similar area will probably need to be repaired for the model to be set up ok. I'll see if I can help you with that a bit later today.

- Michael
Attachments:

  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  twofoot
7945.3 In reply to 7945.2 
Thanks Michael. Do you have any idea why the STL file would export properly?

I wonder if it is my "bad habits" that cause these troubles. LOL

Cheers,

Chris
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  Michael Gibson
7945.4 In reply to 7945.2 
Hi Chris, probably though even after it's repaired it's not too likely to be filleted very well, MoI's filleter has difficulty with these types of areas here:




To put a fillet on something that is smooth in that particular way would mean the fillet would shrink down to a single point at those spots and that just does not work very well in MoI's filleter currently. If you wanted to fillet it all over the best bet would be to have those areas meet up sharply to start with and then let them get rounded off with fillets all in one go rather than having some fillet/blended areas already in place before doing the next fillet.

- Michael
Attachments:

  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  Michael Gibson
7945.5 In reply to 7945.3 
Hi Andrew,

re:
> Thanks Michael. Do you have any idea why the STL file would export properly?

It could be that it's not actually damaged and it's instead a glitch in the display mesher. When you go to do an STL file export, MoI uses a different meshing engine which is more thorough in how it processes things - the display mesher takes some shortcuts for certain things in order to gain speed. Maybe one of those shortcuts is not getting along well with the type of shape there where the top planar face pointy areas.

- Michael
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  Michael Gibson
7945.6 In reply to 7945.3 
Hi Chris, so it looks like your object checks out ok and isn't actually damaged - that one area is a glitch in the display mesher.

So your STL should be ok. But it's pretty unlikely to be able to fillet it with those already existing fillet areas in there... If you have a version saved before you put those in, I'd go back to that one and try filleting from there.

- Michael
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  twofoot
7945.7 In reply to 7945.6 
Makes sense. I was trying to outfox the fillet engine and it looks like my idea backfired. Luckily I am the king of versioning.

Thx!

C.
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  twofoot
7945.8 In reply to 7945.1 
So here's the file without any fillets. Does anyone have suggestions on how to add 6-8mm fillets on the yellow highlighted areas for each spoke? The multiple tapered sections seem to confuse the fillet engine, and what works for one spoke *does not work for all*.

Thx.

Chris

Image Attachments:
Size: 594.9 KB, Downloaded: 15 times, Dimensions: 1330x748px
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  Frenchy Pilou (PILOU)
7945.9 In reply to 7945.8 
Multiple selection and fillet it works for me!


For the opposite fillets this one works
but not the other because individually "external" don't work themselve for any reasons!

EDITED: 3 May 2016 by PILOU

  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Message 7945.10 deleted 30 Oct 2016 by STEFAN

Previous
Next
 From:  twofoot
7945.11 
Thank you for testing!

I was able to fillet the spokes against the inner hub as you did, but the outer fillets failed 4 out of 5 times. So very strange, since they are an array of the spoke that filleted correctly.

Cheers,

Chris

EDITED: 3 May 2016 by TWOFOOT

Image Attachments:
Size: 130.1 KB, Downloaded: 8 times, Dimensions: 358x279px
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  futagoza (STEFAN)
7945.12 In reply to 7945.11 
Hi twofoot,

after testing Pilou's suggestion i came up with this to get all elements filleted.

I cut your model in five pieces and then radial arrayed one filleted element, to obtain a solid.



Regards
Stefan
https://www.behance.net/futagoza

EDITED: 30 Oct 2016 by STEFAN

  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  BurrMan
7945.13 In reply to 7945.8 
""""""""""""""""""So here's the file without any fillets. Does anyone have suggestions on how to add 6-8mm fillets on the yellow highlighted areas for each spoke? The multiple tapered sections seem to confuse the fillet engine, and what works for one spoke *does not work for all*."""""""""""""""""""

There are a few things with this file I didn't like. Some surfaces were not smooth? (Separate outer surface of inner hub and zoom in)

Mostly though the fillets failed because of a slightly twisted, out of plane surface structure which made for terrible fillets. Here is a video where I rebuilt objects.

at beginning I planar (flat snap) spoke objects. Fillet then works ok at 8mm.

  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  twofoot
7945.14 In reply to 7945.12 
Success! Thank you for this rather clever idea Stefan.

Cheers,

Chris
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  twofoot
7945.15 In reply to 7945.13 
Burrman thanks for putting this together.

The file is going to be 3D printed for use as a foundry pattern to cast these wheels in ductile iron. The taper (1.5 degrees) needs to be there to allow the pattern to pull cleanly out of the molding sand at the foundry.

Chris.
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  BurrMan
7945.16 In reply to 7945.15 
Hi Chris,
I noticed tapers on the hub and the inner wall of the outside rim and understand a draft for casting. However, i did not "remove a taper".....

I did view the spokes as a "straight extrude in z" and thats what i did in the video, but thats not the issue i demonstrated in the video. I will re-examine the spokes draft angle and redo the vid if necessary. The issue is with regard to non planar curves being used to generate the solids.
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  twofoot
7945.17 In reply to 7945.16 
Sorry Burrman. I blame it on looking at this on my mobile. ;)

C.
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
Next
 From:  BurrMan
7945.18 In reply to 7945.17 
I double checked the original files spokes and there was no draft set there. Here is the file I was working on in the video.

  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged

Previous
 From:  BurrMan
7945.19 In reply to 7945.18 
Hey Chris,
Just made another video to show the particular area I was talking about.



Notice in the video that regular 2d "planar curves" will only have an X+Y value? so a curve that is non planar will show a Z value also (Its a very small value)

I have a program which will display out to 15 decimals and the Z number on those curves is "0.000065326690674"........

That number changes as you set decimals with rounding. So even the others you saw that said "0" in MoI, were out by some factor.

I think this is what was messing with the fillet calcs (or better said MoI's display mesher with bad trims) and why the STl still calced out. (Number that was out is VERY small)

Anyway, maybe look into why you got non-planar curves will help you to avoid this in the future...
  Reply Reply More Options
Post Options
Reply as PM Reply as PM
Print Print
Mark as unread Mark as unread
Relationship Relationship
IP Logged
 

Reply to All Reply to All