Maya for 3D Printing - Rapid Prototyping
In this course we're going to look at something a little different, creating technically accurate 3D printed parts.
# 1 13-04-2014 , 02:19 AM
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Boolean problems are back...

This my alternate attempt and making a mouth. (Again...non functioning) This fish has a dorsal fin near the tail. I used a short section of cylinder to cut scallops out of the fin. I did about a dozen subtraction cuts. On the last one, the Boolean stopped working and the cylinder and fish body would disappear. I tried saving and closing out, then reopening. So far, no go. Then I tried intersecting a cubic shape with the fish body. Then I selected both and duplicated. My plan is to cut the lower jaw away in the upper model, then to do an 'intersection' with the bottom one which would leave only the lower jaw. But the model still disappears no matter which of the three Booleans I choose. How do I get past this?

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# 2 13-04-2014 , 09:16 AM
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Why r you using boolean for this in the first place. Get rid of the cube, select the faces you want for the lower jaw and detach faces. Simples.

As for boolean - if you are getting it so just the lower jaw is remaining then select them the over way round (body first then cube or cube first then body - soz just woke up cant remember of the top of my head which way round it should be). That should do it. Also make sure your history is deleted.

Fyi your models geo is looking very messy in places. Lots of simple edge loops which are not complete. You may want to look at them as well.


# 3 13-04-2014 , 04:31 PM
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Fyi your models geo is looking very messy in places. Lots of simple edge loops which are not complete.

Booleans? I guess because I'm a largely self-taught newbie and I know they work. The vast majority of MAYA is Terra Incognita to me. But, Detached Faces? That sounds very good. Thanks.

About that messy geometry: I attach a new pic. Are these what you're referring to? They happened when I converted the NURBS to Polys. What should I do about them? Can those edges just be deleted? What is the problem with leaving the as is?

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# 4 13-04-2014 , 05:38 PM
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Try smoothing the mesh. That's the problem user added image


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# 5 13-04-2014 , 06:09 PM
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Try smoothing the mesh. That's the problem user added image

This is related to the incomplete Edge Loops?

# 6 13-04-2014 , 06:16 PM
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Try smoothing the mesh. That's the problem user added image

Here's the smoothed mesh...with a test cube. No matter which order I select the two objects, they both disappear.

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# 7 13-04-2014 , 08:22 PM
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Imagination is more important than knowledge.
# 8 13-04-2014 , 09:19 PM
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Why r you using boolean for this in the first place. Get rid of the cube, select the faces you want for the lower jaw and detach faces.

I've tried selecting the faces I want to detach (and/or edges) and going to Detach Component. Nothing wants to detach. I've dug through about a half dozen MAYA texts, and the only reference to detaching surfaces is when it's a NURBS object and I've already gone to polys. I know I have done this in the past by accident. ("Keep Faces Together" is not selected)

NEXT DESIGN: I did see your post. At my level of familiarity with MAYA, it was a bit jargon-heavy and I passed on it assuming the Booleans could be made to work. For example, I did not know that edges could be extruded. After a bit of experimenting today, I discovered that they could. I had, at one point, selected edges that ran from the eye around the snout to the opposite eye. I then used the Scale Tool hoping to dimple them in a bit. It only puckered the whole snout area, hence, at the moment, I tend to be shy of edge-related solutions.

Why am I being warned off Booleans? What's the problem with them?

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# 9 13-04-2014 , 09:50 PM
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Just use the split poly tool to change you edge flow...........dave

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# 10 13-04-2014 , 11:43 PM
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Just use the split poly tool to change you edge flow...........dave

Very nice. Another tool for the kit. I think that's what I was shooting for originally, but didn't know about the Split Polygon Tool.

But what about detaching?

And why are Booleans bad?

# 11 14-04-2014 , 02:23 AM
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Booleans are bad because they don't work. They are very temperamental, eg causing your geometry to disappear. They also inevitably result in bad topology, and you need to be very careful when cleaning up after them. They usually create more work than they're worth.

Every professional modeler that I have met, myself included, stay away from them like the plague.

Regarding your comment on detaching. Why would you want to do that? You want to get rid of the polygons, so just delete them.

I HIGHLY suggest you invest in some tutorials in order to learn some of these basic skills. Take a look at our free tutorials to get started: https://simplymaya.com/autodesk-maya-...d=23&sub_cat=0


Imagination is more important than knowledge.

Last edited by NextDesign; 14-04-2014 at 02:27 AM.
# 12 14-04-2014 , 04:06 AM
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Booleans are bad because they don't work. They are very temperamental, eg causing your geometry to disappear. They also inevitably result in bad topology, and you need to be very careful when cleaning up after them. They usually create more work than they're worth.

Thanks for laying it out. I will make it a point to avoid them. This is the first app. I've used that had good Boolean power and thought they were heaven sent.

Detaching faces? At first I just wanted an indentation for the mouth like daverave showed me. Then when the detach solution was suggested, I thought I'd angle the jaw down a bit, then use the Merge function to re-attach vetices.

Thanks for pointing me at the tutorials page. I've purchased Pilot Girl, Red Girl, and a monster whose name I can't remember. That's how I found this Forum. Between this Forum, the purchased projects, and YouTube, I'm discovering a lot of techniques. The Tool Bars are no longer a dense mystery.

# 13 14-04-2014 , 09:22 PM
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Try smoothing the mesh. That's the problem user added image

That my friend is defo the thing NOT to do on a model where the geo is a mess. - I am little shocked this came from NextDesign as his work is usually quite strong, and alot of the other stuff he talks about in his replies is correct and makes sense, just not that bit.

Now that you found the "split poly tool" use it to clean up the mess - what you want is to make all the polys 4 sided. You can also do this by deleting some edges. Have a look at the image I have added - This is what it should look like if you were to add all the extra lines in. I would use a bit of both ( add and delete) as long as they are all quads your good to go. (Edit - just noticed I did miss a few lines on that image but you get the idea)

Daverave has shown you a good way to make the jaw - but if you still want the mouth separated and angled what you need to do is.

1) Select the faces you want
2) Make sure your in the "Polygon" tab
3) Then Select - Mesh > Extract - this will separate the lower jaw for you. My bad using the word detach in my last post - wrong word but correct discretion if you get my meaning there.
4) Select lower jaw and "Edit > Delete by Type > History"
5) Then "Modify > Centre Pivot"
6) Press Insert to change the pivot placement to the end of the Jaw. You can do this manually or snap it.
7) Press Insert again and rotate it to the angle you want
8) Select the vertex`s and snap then to the upper jaw so it matches up into the model.
9) Select both and "Mesh > Combine"
10 Fill in the inside of the jaw by iva "Create polygon tool" or "Extrude edge".

FYI - Booleans are fine to use if you know what your doing - I use them all the time to make holes in things. The biggest trick is to start low poly then work up, but many peeps hate them because they cant use them. They even better in Maya 2015.

Hope this helps

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Last edited by tweetytunes; 14-04-2014 at 09:30 PM.
# 14 14-04-2014 , 10:05 PM
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That my friend is defo the thing NOT to do on a model where the geo is a mess.

You misunderstood me. What I meant was that it is clear to see the issue of bad geometry once you smooth your mesh. The bad geometry will become very apparent. I was NOT saying that "if you smooth the mesh all topology problems are solved" as you seem to have read.

Also the statement about people that don't like them can't use them is rather harsh. I understand them just fine, however I can usually do the same thing in less time, and with more control, manually.


Imagination is more important than knowledge.

Last edited by NextDesign; 14-04-2014 at 10:09 PM.
# 15 15-04-2014 , 12:00 AM
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Arr right that makes so much more sence now - i thought it was very odd that you said that, very out of character and skill set.

My statment about the booleans is somewhat true though and plz dont take offence as I did say many people and it was not aimed at you. I do feel they get slammed alot and its because people are trying them without thinking about what they r doing. Its a very useful tool and propably why its in most 3d packages. Different tools for different people, but i think we can both argee not the right tool for the job here yerr


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