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Getting an understanding for using pins/seams with mapping.
Posted: 18 August 2012 06:33 PM   [ Ignore ]
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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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Posted: 19 August 2012 01:22 AM   [ Ignore ]   [ # 1 ]
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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.grin

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.

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HexUV.jpgCarUV.jpg
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Posted: 11 September 2012 12:45 PM   [ Ignore ]   [ # 2 ]
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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

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Posted: 11 September 2012 01:05 PM   [ Ignore ]   [ # 3 ]
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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)

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Posted: 11 September 2012 02:27 PM   [ Ignore ]   [ # 4 ]
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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.grin

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Posted: 11 September 2012 04:55 PM   [ Ignore ]   [ # 5 ]
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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.

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Posted: 11 September 2012 05:06 PM   [ Ignore ]   [ # 6 ]
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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…  smile

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Posted: 11 September 2012 09:14 PM   [ Ignore ]   [ # 7 ]
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I used to help my mom make plush animals.  It was great training.

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Posted: 11 September 2012 11:40 PM   [ Ignore ]   [ # 8 ]
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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

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Posted: 11 September 2012 11:42 PM   [ Ignore ]   [ # 9 ]
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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.

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Posted: 12 September 2012 12:10 AM   [ Ignore ]   [ # 10 ]
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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!!

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Posted: 12 September 2012 12:35 AM   [ Ignore ]   [ # 11 ]
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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?

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Posted: 12 September 2012 03:16 AM   [ Ignore ]   [ # 12 ]
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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?

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Posted: 14 September 2012 05:44 AM   [ Ignore ]   [ # 13 ]
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JoeMamma2000 - 12 September 2012 03:16 AM

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”.

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?

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Posted: 14 September 2012 05:45 AM   [ Ignore ]   [ # 14 ]
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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?

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Posted: 14 September 2012 05:48 AM   [ Ignore ]   [ # 15 ]
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JoeMamma2000 - 11 September 2012 04:55 PM

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.

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.

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