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Getting an understanding for using pins/seams with mapping.
Posted: 14 September 2012 06:05 AM   [ Ignore ]   [ # 16 ]
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The term UV , or to be technically correct (U, V, W) in mapping, comes from the use of X. Y and Z, as the basic coordinate system for the 3D space, and U, V, are simply Different letters of the alphabet used to describe the position of this different space, and avoid confusion for programming.

Pinning and seams as Joe and others have pointed out, all have their origins in the garment industry, where a paper pattern is placed onto a sheet of material, and Pinned to it, before defining seams, and cutting it out to then stitch it together.
most of the time, the position of the pattern (template) is adjusted on the material to create an even look to the final garment, and to avoid waste.

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Posted: 14 September 2012 06:19 AM   [ Ignore ]   [ # 17 ]
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EDAGE! I can pretty much do some good work in HEX and CAR as for UV Map unwrapping BUT on more complicate objects liek a human head or maybe a Shirt I get inconsistent results… And have to do a lot of moving stuff around…

I have tried to use PINS but am even more bizarre results…..

Could you please explain the use of PINS and where and when they should be used?

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Posted: 14 September 2012 09:56 AM   [ Ignore ]   [ # 18 ]
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Garstor - 14 September 2012 05:45 AM
UVDan - 11 September 2012 12:45 PM

I have no help for you.  I am as lost as you are.  I keep returning to UV Mapper Pro where I have some familiarity.  I await to see what the real pros have to say

I’ve heard of this program too. I wonder how it compares with what Roygee uses?

I have several videos on my YouTube channel about UV Mapper Pro and I will be uploading more as time goes on.

http://www.youtube.com/user/UVDan?feature=mhee

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Posted: 14 September 2012 10:55 AM   [ Ignore ]   [ # 19 ]
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HI Richard wink

You always ask the most difficult questions smile

Unfolding a 3D head shape isn’t as easy as unfolding a t-shirt, and exactly where you define the seams is probably more important that whether you use Pins or not.

Both Seams and Pins depend on what “you” want to get and how you want to “texture” the model.
For example:
You could define a seam from the back of the neck, across the top of the head and down the nose to the front of the neck, which would give you a Split with a left and right side of the head. or you could define a seam from the back of the neck to the top of the head, and set a couple of Pins (one on either side of the neck) (see pic) which would give you a single unwrapped head.

For a Clothing item, like a t-shirt or trousers (pants) the best idea is to follow the seams you would find on a real garment.
for example,. A T-Shirt, would have two panels (front and back) with seams at the sides, and at the top where the two panels would connect. (see pic2)
If you need pins they would be at the top or bottom depending on what you want.

Or,. you could define the Arms of a shirt as separate sections with a seam to unwrap them, so, it’s not a simple question to answer, and one method is as valid as another.
Much depends on the mesh and how you want to split that, and whether you want a single panel or different sections.

 

 

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Posted: 14 September 2012 06:34 PM   [ Ignore ]   [ # 20 ]
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So PINS should be at the top and or bottom of a mesh?

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Posted: 14 September 2012 07:26 PM   [ Ignore ]   [ # 21 ]
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Why don’t you look at the texture templates for M4, V4 or M3 or V3 and see how they’re unwrapped? Might give you some ideas on how to do it. Just because you look at it doesn’t mean you have to do it that way, or even use the figures. Then again, if you build your own character and unwrap it in a similar way, you may be able to use the textures. As long as you’re not distributing the model and textures, but using it for your own use, there should be no usage rights issues.

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Posted: 14 September 2012 07:41 PM   [ Ignore ]   [ # 22 ]
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I think the challenge with the implementation of “pins” in Carrara (and also in Hex, I believe) is that, as far as I can tell, they really don’t do what you’d expect they should do, like in other apps. Which is why I suggested not to worry about pins right now if you’re learning, because they are, at best, of limited usefulness for the vast majority of your work.

I think the point with pins “should” be that you pin a vertex to a specific point on the UV grid, with a corresponding texture underneath. So if you want a particular vertex on your human character’s face, say, the tip of the nose, to line up with the corresponding point on the underlying texture image of a face in the UV view, you should be able to select that vertex as a pin, move it to that point on the UV grid, and have subsequent unfolding operations or relaxing or smoothing or whatever other operations keep that vertex in place, right on top of the nose on the image, while the other vertices unwrap around it.

But as far as I can tell, it doesn’t do that. I could be all wet, but I’ve never been able to get it to do anything close. If anyone knows how they can be more useful, I’d love to hear about it.

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Posted: 14 September 2012 09:07 PM   [ Ignore ]   [ # 23 ]
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Roygee - 11 September 2012 11:42 PM

BTW - good idea to do the UV mapping once the model is done, but before smoothing.  That way its a lot easier to locate your main edge loops.


I mostly make clothes.  I do unwrapping at low res (usually 2k or so polys for a shirt) but with seams meshed in (realistic clothes should always have the seam meshed where the UV is going to break, in my opinion - unless you’re working with armor or other not-really-cloth items). 


Then I pin the primary axis of each UV island, excluding the very edges, and do my subdivision, smoothing, and sculpting of wrinkles.  Sometimes I forget and need to curve the edges or something later on, in which case I update the UV with Blender’s Live Unwrap using my existing pins.  If the very edges aren’t pinned it updates reasonably well at 8k or so.  As an item gains polygons in the exponential progression of subdivision, updating quality falls (at least in Blender), so I really try to get the main UV done before the number of polys becomes two-digit or more.

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Posted: 15 September 2012 12:41 AM   [ Ignore ]   [ # 24 ]
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Just to give some idea of the limitations of Carrara UV unwrapping.  This is the “Babyface” model which comes with Hexagon.  I’ve unwrapped it using the standard method for heads - seam up the back of the neck to the forehead, then a seam across the forehead.  One pin in the centre of the forehead and and another on the bottom vert in the centre of the front neck.

Seems to have unwrapped perfectly in Carrara - until I start painting it, then all sorts of strange things happen - apply paint in one place and it also appears somewhere else.  This is a result of overlapping UV’s.  The problem in Carrara is that you can’t see these - all you get to see is verts.  Also, on my machine anyway, it’s virtually impossible to move anything, the lag is so bad.

Now this is not that bad if all you want to do is slap an even texture on it, but no good if you are wanting detailed texture.

i take it into UU3D - or Hex - and it is immediately obvious what the problem is - see the bright spot in the middle of the second pic?  Those are overlaps - and there are many more on the unwrap.  Now in Hex and even more so, UU3D, there are many tools to manipulate and fix those problems.  What I also found in UU3D is that the model is not all that well made - there are holes around the edges of the ears where the verts aren’t correctly welded.  Hex and UU3D also have the advantage that you can put a checkerboard texture on the UV map to visually identify anomalies such as overlaps, stretching and bunching.

When I do exactly the same unwrap in either Hex or UU3D, I get a perfect unfold, without overlaps.

As you can see in the third pic, (if they appear in the correct order) pinning is absolutely essential for organic models - this is the same model unwrapped without pinning.  So, for organic models at least, it is no good concentrating on seams and learning pinning later - they are equally important from the start.

Pinning also has nothing to do with pinning it to a texture map - pinning gives fixed points around which the UV’s unfold symmetrically.

The workflow for me is model in Hex, export as .obj, import to UU3D to UV map, export as new .obj, into Daz Studio for rigging, into Carrara for texturing and animation.  I use Carrara for exporting the UV map, if I’m going to do the texture in a 2D application.

UU3d has a free trial, which is only limited in that it won’t export the result - and you can’t cheat by doing a screencap, either.smile

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Posted: 15 September 2012 01:07 AM   [ Ignore ]   [ # 25 ]
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Roygee - 15 September 2012 12:41 AM

Pinning also has nothing to do with pinning it to a texture map - pinning gives fixed points around which the UV’s unfold symmetrically.

I’m sure you meant to add “...in Carrara and Hex”. Because that’s certainly not necessarily true to the rest of the 3D world.

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Posted: 15 September 2012 01:56 AM   [ Ignore ]   [ # 26 ]
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I wrote exactly what I meant - if you have any evidence that it works differently elsewhere, I’d be happy to see it - always ready to learn.

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Posted: 15 September 2012 03:26 AM   [ Ignore ]   [ # 27 ]
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Roygee - 15 September 2012 01:56 AM

I wrote exactly what I meant - if you have any evidence that it works differently elsewhere, I’d be happy to see it - always ready to learn.

Here’s just one example from the Blender manual:

“Using the Pin (P) command on selected vertices forces them to stay put between multiple unwrap operations, pinned in their current location. Any subsequent Unwraps will not move them.”

I’ll let you search any other applications if you’re really interested in learning.

Have you ever actually used any other UV unwrapping apps?

 

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Posted: 15 September 2012 03:56 AM   [ Ignore ]   [ # 28 ]
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Oh, and Modo was close at hand, so here’s the same thing on pins from Modo:

“Pinning allows you to define specific vertices on the UV map that will act as control points or “pins”. When the relax iterations are set above 0 the free vertices will smooth themselves out between the pinned vertices.”

Lemme guess…semantics, right?  Or maybe you’re waiting for Andy to repeat what I said again before you believe it?  smile

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Posted: 15 September 2012 04:13 AM   [ Ignore ]   [ # 29 ]
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Roygee - 15 September 2012 12:41 AM

Pinning also has nothing to do with pinning it to a texture map - pinning gives fixed points around which the UV’s unfold symmetrically.

Oh, and since I’ve learned not to assume any prior knowledge here, keep in mind that when you pin a vertex to a UV map, you are pinning it to the underlying texture map. That’s what pinning is in many other apps, it’s pinning the vertex to a texture map so that it doesn’t move during subsequent operations.

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Posted: 15 September 2012 12:27 PM   [ Ignore ]   [ # 30 ]
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Thank you - that confirms exactly what i was describing.

Don’t know how you figure that to mean it pins the UV’s to a texture map, seeing that the UV’s have to be generated and the map laid out before they can be used as a template.  Once inside your 2d painting app., there is no way to alter pins to fix them to anything.

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