Getting an understanding for using pins/seams with mapping.
moea
Posts: 0
I really need some assistance with the whole concept and utilisation of seams and pins for mapping. I just don't get the concept. Is there a useful tutorial anywhere? please advise.
I kind of have it in my mind that if i create a pin(s) they become stationary points and with seams the map will unfold from that fixed point. Obviously, it's not working for me.
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From what you wrote, you do understand the concept. The purpose is to get the 3d mesh unfolded flat so that you can paint, etc. on it.
It will unfold along the seams and the pinning will hold the pinned UV's in place so that it unfolds symmetrically. Easier said than done Lol.
Take a simple cylinder with caps. The standard method would be to cut a seam around the top and bottom ends to isolate the caps. Then a seam along the length to split it. Then two pins on the opposite side to the lengthwise cut, one vert in from the cut.
This works in every UV mapping app I've use, except Carrara. Hopefully someone with more knowledge of Carrara's strange UV mapping process can help us both out.:-)
The pics show what I've described in Hexagon and Carrara - the Hexagon one is clean, although disproportionate, but the Carrara one is a mess.
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 apply planar mapping usually changing the axis until I get something usable,
then I can paint it
you can also select and drag the vertices to where you want them on simple objects to map textures to them
(no luck with most Daz clothes though, too many polys, they lag then fly out of place wildly)
Oh, I've since figured it out - you simply ignore the default UV mapping C gives you and get on with it as is done in other unwrappers.
Wouldn't use it for anything complex, though - I use UU3D - many more options for unwrapping complex meshes.:-)
I would repeat my same old recommendation that I give everyone here, which is to read a book on CG basics before playing with software, but it just makes everyone real angry, so I won't.
Instead I'll give my 10 minute version of UV mapping. Of course there are a billion tutorials out there on the internet if you want to search.
My best analogy for UV mapping is this:
If your mom ever did any sewing and you saw what she was doing, you know something about it. She went to the store, bought a "pattern", then bought some fabric, laid the pattern over the fabric on a flat "2D" table, cut out the pieces, and sewed them together (at the seams). And when all the pieces were sewn together, it fit on your 3D body.
UV mapping is the reverse, where you take your 3D body and make a flat, 2D pattern.
Now, go to your closet and grab a pair of pants. Look at them. Look at where the seams are. There's a seam down the right side, one down the left side, and one along the inside of the legs and thru the crotch. Pretty much just three seams to make two pieces of fabric fit on your 3D body.
It's exactly the same thing with UV mapping, except you're trying to apply a 2D texture image to a 3D object. If you were going to apply a texture to a pair of pants for your 3D character, you'd make the same seams that are in a real pair of pants. The fabric is the texture you want to apply.
It's almost as if someone had spray painted a pair of pants on you, and the paint turned into fabric, and you had to figure out how to cut the fabric into the fewest number of flat pieces. That's why it's called "unwrapping".
You are basically trying to figure out how to take a 2D texture and apply it to a 3D character. And the best way to do that is use the same techniques that clothing makers have been using for centuries.
Right now focus on seams. Pins are useful sometimes, but you first need to really grasp the concept of seams.
By the way, and this is very important...
UV mapping does not alter in any way the object you are applying the texture to. It merely is a way to define for the software how you want the texture applied. You are telling the software "okay, make believe there's a seam along these edges, and do this unwrapping, but don't mess with my model or I'll kill you".
Also, and this is what I hate about having programmers write instruction manuals...
"UV" is a term that is useless to users, but means something to programmers. In the same way that you define three coordinates in the 3D view (you move things in the X, Y, and Z coordinates), a 2D texture or pattern has only two dimensions, the height and width. And they decided to use some letters of the alphabet that weren't being used elsewhere, so they chose U, V, W, X, Y, Z to define the height and width.
I suppose instead they could have used VW unwrapping, but I think that's used elsewhere... :)
I used to help my mom make plush animals. It was great training.
Simple to remember - U is for UP - V is, VERY logically, horizontal. Lol
Pinning is what makes it unfold nice and flat and symmetrical, without the dreaded overlaps. Also very simple in concept. Take Joe's jeans as an example. Pinning pins down part of the material so the rest unfolds away from the pin - just like your mom's paper pattern. If you were to cut the seam up the inside of the legs and up the fly and back of the bum (most logical), you place pins on the outside of the legs, on the bottom of the cuffs, directly opposite the cut and and, on the same edge, at the top - that's four in all.
You can then line them up and weld them into one.
In the pic, the green lines show the seams and the red dots the pins.
OH dear - I used fast reply - no picture posting - will post another
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.
yeah that confuses the crap out of me as v should be vertical and H horizontal, it should be HU or is that UH mapping!
but x is horizontal, y vertical in most but not all things INCLUDING Carrara where Z is vertical INSTEAD!!!
so I get very disorientated!!!
I mostly look at the uv shapes and the image and in Carrara it IS INDEED always illogically sideways!!
OK - here's one that's a bit more logical - V is half a W for WIDE!
Something that makes little sense - long before 3D was invented, charts always used X for horizontal and Y for vertical. Along came 3D and they brought in an extra dimension, depth. The logical developers simply added Z for the new dimension, while the illogical ones replaced Y with Z and used Y for depth - what were they thinking?
BTW, just to be perfectly clear, Carrara's modeller and UV mapper suck. Not a little, not "kinda", they suck totally.
So if you're having problems, it's not you, it's a poorly designed app. Hex is far better, but still not what you'd call "good". The logic Carrara uses for unwrapping is demented. And for the same shape, it changes depending on, I don't know, the weather or something. You unwrap a cylinder one time, you do it another time and get a different result.
I mean, what kind of algorithm are they using to get nonsense like this for a simple cylinder?
In all honesty, I was thinking that it was me. I am trying to better my skills and understanding of UV mapping.
The semi-maligned / semi-praised Model Master training from Dreamlight has helped a bit. Combined with PhilW's training and plenty of threads here on the forums, I think I am finally approaching a "getting it" state. Now I need to move toward "excelling at it" state.
Roygee: I am curious about that Ultimate Unwrap software. Do you use it often? Near as I can tell there is no native Carrara support for it, so I guess there would be an export/import step with OBJ format to use it with Carrara?
I've heard of this program too. I wonder how it compares with what Roygee uses?
Actually, I'd be very interested to know what CG books are/were sitting on your shelf. I think your advice about learning software-agnostic basics is excellent and I'd be up for doing that.
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.
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?
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
HI Richard ;)
You always ask the most difficult questions :)
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.
So PINS should be at the top and or bottom of a mesh?
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.
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.
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.
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.:)
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.
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?
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? :)
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.
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.