Exact Center of Tops and Bottoms

I know I read this info somewhere before but after an hour of searching I can't find it.
In photoshop I use the pixel ruler. Over Chip's or Robin's wonderful templates, where can I place a guideline for the EXACT center of the front and back of the top and front and back of the pants? Also if anyone know which side of AVPainter is slighty off let me know - I know there is a pixel missing in there somewhere. Thanks cyber friends.

The centre, verticle line in the UV map should be the exact centre.

However, when I made an outfit that had a line down the centre, I had to move the pants line two pixels to the left to have it match up to the front; and then to have it actually sit centrally in the crotch, I had to make a pair of diagonal pixels to bring it back to the UV line.

Thanks Seshat - Yep I know there are lines on the template. The uv line has a thickness tho and maybe I have tapped my temp off a bit - it seems to be a judgement call on which side of that line is indeed the center. I saw a posting many many months ago where Chosen (pretty sure it was Chosen) listed the exact placements on a ruler - that was very helpful to me. Unfortunately when I moved recently I lost my rl sticky notes.

It wasn't me, Jdiva, sorry. At least, I don't think it was.

Anyway, you're right that the lines on the templates do have thickness to them. But in most places, that thickness is two pixels, which is exactly what you want. Due to anti-aliasing, you'll see a dark line with a lighter line right next to it. It's a pretty safe bet that the "center" in those cases is the border between the dark and light lines.

For example, the image below is is of the font upper body, pit of the stomach area, zoomed in about 3200%. The "center line" at that point is two pixels wide, and the other converging lines all appear to meet right at the border between the two. From that, I feel pretty confident in calling the center of the front upper body the 262 px mark, which is where put the guide you see in the picture. And from that, we can say that anything at 261 and leftward will be be on the model's right side, and anything at 262 and rightward will be on the model's left side.



You can pretty easily find the "centers" of the other sections by looking for similar convergences on each.

We can't really call that an exact science, though, since we don't really know how per-pixel accurate the templates are. There are two reasons for this. First, since the templates are twice the size of the composite-baked outfit textures in SL, it's possible to be off by a pixel in one direction or the other on the 1024x1024 template, and then end up in the right place on the 512x512 bake (or not). Or the opposite could conceivably happen as well. You could be in the exact center on the 1024x1024, and then end up off by one pixel in the 512x512. It all depends on how the reduction is being done. It would take some experimentation to figure it out perfectly, and I've never actually done that. Perhaps someone who has will chime in.

Second, to get a precisely accurate measurement, we'd need to analyze the actual UV setup on the model. We need to know if edges fall on exact pixels, or in between them, and then we need to know which pixels we're talking about.

All of that is worthwhile information, so I'll probably look into it when I get a chance. I never actually have. Again, perhaps someone who's done it will have some better information.

In the mean time, I wouldn't obsess about it too much. If your center line is off by a pixel, it's very unlikely to be noticeable. As long as the upper and lower body match each other, that's all that's important. And making that work is really easy. Just draw a vertical line on each, apply them to the avatar, and see if they line up. If they don't, move one or the other over by a pixel, and check again. When you've got a match, make note of the numbers, and call it a day.

If perfect symmetry is a concern, again, I wouldn't obsess about it. No one's gonna care that that spaghetti strap is 120 pixels from the "center" on one side, and 121 pixels from it on the other, or that those two pants pocket aren't per-pixel equidistant from whatever marker you're calling the "center". As long as the seams match from front to back, and from top to bottom, that's all that's important.

Woops Chosen - sorry about that perhaps my memory has you down as the Chosen one on all things resolutiony. Thanks for answering and you are right I am getting way to anal and picky... this came about mostly from an obsession I had with AVPainter - I swear one side of that booger is a pixel smaller that the other. Not a huge deal except when I do a spagetti strap thingie one side is perfect and the other is off and I go nutty cause I just cut and flipped one side to mirror it. So in my thinking they should be the same. I suspect there is a simple explaination out there. If you do get those "exact centers" let me know. When I zoom in the front top is pretty easy but the back and bottom UV lines seem lighter or less clear. I wonder if part of that issue is because the bottom is not the same size as the top. Yeah I had those percetages on the lost sticky notes too. Sigh.

Real humans are not symmetrical. One of the things that makes avatars look 'barbie-like' is perfect symmetry.

So it's actually an asset for our clothing to be not perfectly symmetrical. Oh, sure, it's good for it to look almost symmetrical: but don't obsess over one or two pixels. Those one or two pixels off are a GOOD thing.

Abu Nasu made PSD vector templates if you don't feel like extrapolating from anti-aliased lines where the centers are.

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