Watertight snaps All  1-20

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 From:  fraser
3345.1 
I'm having problems modelling a watertight solid on a 12 x 12 inch grid with snap to grid set to .5 inch. Some of my curves seem to miss the intersection unless I turn off object snapping first. Any suggestions or tips? f

ps The December beta performed fine on my MacBook Pro under Fusion 3.02

EDITED: 24 Feb 2010 by FRASER

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 From:  Michael Gibson
3345.2 In reply to 3345.1 
Hi fraser, generally object snaps take precedence over the grid snap.

So if you want something to snap to the grid only and avoid things like the endpoints of lines or other objects, then it is normal that you would need to turn off object snap to make that happen. The reason why object snap is able to be toggled on and off is because there are times when it can get in the way.

But if you are running into something else, could you please post the 3DM model file and maybe show me what area in it you are trying to draw on where you are not getting the results you want?

There is a mechanism that kind of combines grid snap and object snap together in certain circumstances - that's why you have both enabled and you are snapping on to a line that is running along the grid axis directions. That will enable the grid intersection points with the lines to be snappable as if they were object snap points. But that will not happen for just any curve going in all directions because it would be too time consuming to intersect every kind of curve with the grid all the time.

Is that the part that is possibly confusing you? I mean that you don't have to turn off object snap to see the grid snap when you are on axis-aligned lines?

- Michael
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 From:  fraser
3345.3 In reply to 3345.2 
I think I have my confusion about snaps cleared up but I can't get a watertight solid by boolean merging what appear to be contiguous surfaces. I suspect that they actually aren't for one reason or another. As I couldn't get a sweep 360deg through six profiles, I resorted to splitting the sink's rim into two pieces: a loft for one half and a sweep for the other which doesn't render cleanly. Any ideas anyone? f
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 From:  Michael Gibson
3345.4 In reply to 3345.3 
Hi fraser, yeah a non-watertight sink is not good! :)

It looks like you may have a few duplicated surfaces stack on top of each other in this model currently, like if I select a surface here you can see how it only partially displays:




That can make things more difficult for the booleans, you'll want to just delete some things like that.

Also it looks like the pieces do not quite touch in a simple manner, there is a slight separation and little skinny surface here:






Anyway, those are some of the problem areas - I'll take a look and see if I can help to clean this up.

- Michael

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 From:  Michael Gibson
3345.5 In reply to 3345.4 
Hi fraser, just one more tip - if you have surfaces that are touching each other edge-to-edge then probably you want to use the Edit > Join tool to glue them together, rather than the Booleans.

The Booleans are more intended to be used when pieces need to be cut with one another and some kind of material being removed in order to combine the pieces.

If you don't expect for the pieces to be cut, then Join will probably be the better tool.

- Michael
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 From:  Michael Gibson
3345.6 In reply to 3345.5 
Hi fraser, but also in order to be joined, the edges between 2 surfaces have to be touching pretty closely, they need to be within 0.005 units of one another.

There are some areas of your model that are not quite within that distance of one another.

For example this area here:





That gap is something like 0.0053 units in size, so it's just barely not close enough to be joined. I'll probably try to do something like recreate that vertical surface by lofting in a new one between the other ones edges. It looks like you may also be running into issues with the refitting mechanism not quite fitting tight enough to some of your shapes here, so setting the option in Loft for "Profiles: Exact" may help to avoid the fitting problem and get a more precise result. By default Loft can try to do a refitting process to try and produce more simplified surfaces but you can override that with the Profiles: Exact option.

- Michael

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 From:  Michael Gibson
3345.7 In reply to 3345.1 
One thing you might try as a general modeling technique is instead of building each individual surface to its final edges from the start, try building pieces that are somewhat more extended and then cut them back to make the final result.

Like for example here you've modeled the basin surfaces so that the hole in the bottom is part of the surface directly (and same with all the other surfaces). Instead you might try having the basin pieces be kind of extended and then produce the hole by booleaning away a circle drawn in the top view that cuts a circular hole through there.

Carving pieces to common cutting objects like that can be a bit easier to ensure that you get matching pieces..

- Michael
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 From:  Michael Gibson
3345.8 In reply to 3345.1 
Hi fraser, also another problem area where pieces are not meeting up cleanly is in this spot:





So there are 3 areas (2 along the sides, I posted a screenshot of 1 side earlier) where there were some kind of little gaps or misalignment between pieces which has resulted in some little slivery surfaces.

I've nearly got a solution for you (which will include some small slivery surfaces in those areas though), one trick I used was to temporarily scale your sink down by 1/10 in size which also shrinks the gaps between edges to put them within join tolerance. Also I drew a circle that was just barely larger than your bottom hole and trimmed the basin surfaces to it to give them a good juncture.

- Michael

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 From:  Michael Gibson
3345.9 In reply to 3345.1 
Hi fraser, I've attached a version here that has it joined together into a solid.

Those little fragmentary surfaces will tend to make it a lot more difficult to get things joined together though, they also tend to cause little tiny edges as well.

In this solid version I've rebuilt a couple of areas, and used the "Scale down then join" trick to get some pieces to join as well.

- Michael
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 From:  Michael T. (MICTU_UTCIM)
3345.10 
Hi all.

Here is my re-built version as a solid. (for what it's worth) :-)

Michael T.
Michael Tuttle a.k.a. mictu http://www.coroflot.com/fish317537

EDITED: 4 Nov 2010 by MICTU_UTCIM

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 From:  fraser
3345.11 In reply to 3345.9 
Thanks! I cleaned up my first draft myself and rendered it with Indigo via Sketchup. I managed to join all surfaces but can't get a solid out of them. One or more of my edges must not be contiguous? Some feedback might be useful there. If Moi turned contiguous surfaces purple, for example? f


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 From:  Michael T. (MICTU_UTCIM)
3345.12 
Hi Fraser,

I did notice a few edges that needed to be merged together. That cleaned things up quite a bit.

Michael T.
Michael Tuttle a.k.a. mictu http://www.coroflot.com/fish317537
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 From:  BurrMan
3345.13 In reply to 3345.11 
Using the "Get Naked Edges" script from the Petr's MoI page at the resources tab of moi3d.com will show you where the issues are.
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 From:  Michael Gibson
3345.14 In reply to 3345.11 
Hi fraser,

> I managed to join all surfaces but can't get a solid out of them.

The attachment that I posted above had your object as a solid, here is a direct link to it:

http://moi3d.com/forum/get_attachment.php?webtag=MOI&hash=c925ce1225c8eb1ca889a9c83cb358d7&filename=mezzo_solid_3DM.zip

If you need to have a solid, will that version above work for you?

Like Burr mentions, the best way to see why your object is not a solid is to set up the "select naked edges" script on a shortcut key and use that.

Here is a direct link to that script:
http://kyticka.webzdarma.cz/3d/moi/#SelectNaked

To set it up, you go to Options > Shortcut keys, push "Add", then put in the key you want to trigger it on the left-hand column and paste in the script for the right-hand "Command" column. Then when you push that key all the unattached edges in your model will get selected so you can see where they are.

- Michael
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 From:  fraser
3345.15 In reply to 3345.14 
I managed to get a solid out of my 32 surfaces when I swapped a network of curves for four 90 deg rail revolves which produced matching edges (not naked?). Now I'm trying to filet them. Although the two lower quarters work, I can't figure out how to filet the lofted edges of the other two. I thought that replacing them with a sweep might work but I keep getting some odd edges. I'd be happy to revert to a loft if someone can suggest how to filet around a joined surface. f




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 From:  Michael Gibson
3345.16 In reply to 3345.15 
Hi fraser, is it possible for you to post the model that you are trying to fillet?

Fillet does not like to have things like little tiny edges or edges broken up into many segments when they could be a longer single edge.

You could try the Merge command (which you need to type in by pushing Tab and then type "Merge" and push Enter) which will glue fragmented edges that touch each other smoothly into longer edges.

Another possibility for getting a fillet in some difficult situations is to use the surface/surface filleter instead of the edge-based filleter.

To use the surface/surface filleter, you use Edit/Separate to break your object down into individual surfaces and select 2 surfaces and then run the Fillet command.

That does a somewhat different mechanism for calculating the fillet which analyzes the surfaces more directly to generate it rather than trying to follow along the edges. The edge-following one can be more convenient since it can do things like build corner patches where several edges come together, the surface/surface one does not do things like corner patches.

But the edge-based filleter has a more difficult job to do so it can get confused and fail somewhat more easily than the surface/surface filleter.

It's hard to give very specific advice about this by just looking at a screenshot instead of examining an actual model though.


Filleting in general has a lot of difficult calculations that it needs to do so it is pretty easy for it to fail if you've got problematic geometry like little slivery surfaces, tiny edges, lumpy or bumpy surfaces, surfaces that fold back on top of themselves or have self-intersections. Also surfaces that touch each other with only a slight crease between them (instead of touching smoothly or more distinctly sharply) can tend to be difficult.

If I could examine your model that would help me to see if you are running into any of those kinds of things.


- Michael
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 From:  fraser
3345.17 In reply to 3345.16 
That information helped a lot. An edge filet worked for me where a surface filet produced some odd results. f
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 From:  Michael Gibson
3345.18 In reply to 3345.17 
Hi fraser, it looks like you have a good result there now!

Do you have any more problems that you need solved with this, or is it finished?

- Michael
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 From:  fraser
3345.19 In reply to 3345.18 
One quick question: if i need to change the geometry of a model can I somehow glue generated surfaces to their curves and just edit them? Or do I need to delete the original surfaces, edit the curves, and resurface? f

ps The scale down and join trick works perfectly!
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 From:  Michael Gibson
3345.20 In reply to 3345.19 
Hi fraser,

quote:
One quick question: if i need to change the geometry of a model can I somehow glue generated surfaces to their curves and just edit them? Or do I need to delete the original surfaces, edit the curves, and resurface?

Currently you'll generally need to do the delete, edit the curves, and resurface method.

In the future I want to work on adding in a deeper history mechanism so that you could be able to do things like update a final model by adjusting some of its original input curves.

Right now that does work to a certain extent like after you do a sweep you can adjust the input curves and the sweep will update. But if you do some other kinds of edits to the sweep surface like boolean or trim them then you won't be able to do the automatic history update after that.

- Michael
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