UVMap issues, and ideas..

[Kagehi]

Ok. We all know the problem here. If you want to be really picky about selecting where the map is cut up you "may" get a usable map. Or, even if you are careful, you might get "twisting", where you have no flat pattern, and parts of the pattern overlap. And, of course, the autouv functions "do not do well" at spacing the parts, to prevent overlaps, even when they otherwise fail to twist things into a pretzel.

Oh, right, and, unless someone fixed it, there is still no option, never mind a default result, to make it, "generate a new uvmap", instead of mashing together the prior map for an object, with the new one. The only solution being to make sure you rename the map, as soon as you make it, so that it the next map generated will be unique (it always uses the default name for such new maps, and the code doesn't do, say auv1, auv2, etc.) There may be cases where you "miss" geometry, and having it tack the "new" map over the old one, as new geometry, would be useful, but even that would mean "finding space" in the existing map, not slapping a new one, over top of the one you already have.

These are the things broken currently. And, mostly, they are fixable, and just annoying. Yet... Here is the thing. Because they are broken, the following ideas **are not possible**:

1. Smart Unwrap - This is more or less what needs to be fixed anyway. Blender does this, and it avoids overlaps, and twisting, to produce a nice, neat, clean, map, which fits handily into the space for the final texture.

2. Bake normals to texture - This "requires" that the unwrap work well. Otherwise, well, its kind of hard to bake displacement/normals onto a texture, which is twisted up, or overlapping. Similar option for "shadows" and possibly "specular".

Note.. Someone already put out, at least in one of the threads, a simple plugin to export normal maps. And, apparently, the only difference between these and displacement maps (or Second Life "sculpties") is the image resolution, and whether or not the shape is deformed, or only the texture is "bend" to make it look like it is a different shape. They are all the same thing, otherwise. Though, normal/displacement are often applied to flattish surfaces, to reshape them, not whole objects (where SL sculpties displaced the geometry of a "fixed" number of vertices, without changing the texture appearance, or adding geometry). But, from what it looks like it does for "making" the map.. they might as well all be the same things.

3. Convert to new map. - This was an odd idea I had, which would be useful, but.. not absolutely necessary. But, it would be a neat trick, in any case. It means, basically, you bring up the UV window, then "select" parts of your existing map, which you want to be a separate texture. You can then "remap" them to a new map, erasing them from the existing one, in effect, separating out the result into two uvmaps, and two textures.

Why would you want to do this? Well, maybe you have a "default" texture, you where working with, but, later on, you decide that you need part of the object to me mappable to something else. You don't need to redo the texture this way. You just "break" the existing map, for the texture you already have, into several parts, so you can still use the original texture, without any problems, or you can create new textures, with just the parts needed, to change those details.

The existing method would require remapping the entire bloody thing, into multiple new maps, and, without a mess of fiddling, remaking all the textures, as well.

4. Autouv to existing map (actually, not sure of the name for this)- This is the one that I would really like to see, and it "fits" right in with the baking of normals (and shadows, for that matter, if the option was added).

Now, its possible a smart unwrap "could" in many cases "map" a low rez, and high rez, object to nearly identical uvmaps, so you could do minimal tweaking to get it right. But.. I think there is a better option. The idea is to be able to pick an existing uvmap, and "mark", either the outer edges, or maybe more than that, then use it as a template, for unwrapping another object. This means that you would unwrap the "low res" version of your object, to the textures you need. You then use "those" uvmaps as "templates" to determine where the high res map lines up to the same texture.

Presuming this can be done, it would mean that you could them "bake" the high res object to a normal texture, and the result would line up with the other textures exactly, without needing to tweak any of them, to fit properly. Since they already "match" the place they should be on the low res object, no tweaking would be needed at all.

I have no idea how/if blender handles this, but I suspect its.. probably the same way you would have to in Wings 3D now - load the texture you intend to use onto the high res mesh, then tweak the heck out of the bits of its uvmap, until they sort of line up right, before backing the normal/shadow maps from that high res copy.

In any case. Most of these things either won't work, won't work well, or would be a nightmare to do, with uvmapping broken the way it is. Just.. making uvmaps at all, if you are not paying attention, can be disastrous, due to the, "I'll just use the existing map, and tack on the new bits you just unwrapped to that, OK! ", way it currently doesn't handle maps and objects.

[ggaliens]

I have used AutoUV a good bit over the last year. I would agree there are aspects that need revision and more attention ... but it does pretty well what it initial set out to do back in early Y2K years. Yeah ... I think if you don't pick planar ... then you get size variation that may be hard to deal with ?

[ggaliens]

Minor issue / question I had from today. Can I get the lengths to stay proper ... or is this a LSCM thing ?

[micheus]

ggaliens, I'm not sure about how you create your objects and unwrapped it, but I create some similar to try to show you that for this kind of regular object that distortion should not happens:

even using Unfolding or Projection Normal in AutoUV (without set any cut edges, since the hard edges are used for that too) (2nd) you should get the four pieces as shown in the picture (3rd) and by using Stitch in the base triangle you should be able to glue the pieces and get a regular shape as shown in the last box (4th).

[ggaliens]

I'm going to need to "stitch" 300, 400, ... or even 900 or more Tetrahedrons. So I'll need to see what parts of stitch can be available to a plugin.

[micheus]

I'm going to need to "stitch" 300, 400, ... or even 900 or more Tetrahedrons. So I'll need to see what parts of stitch can be available to a plugin.

Usually we need to unwrap the mesh with care. Is impossible to guess how the user wants to unwrap the model - we can just try some options.
In your case, with so regular shapes, I know you probably would be able to automatize the process.
The use of Stitch was necessary just because all those edges were set to hard edges and - as I told - the hard edges in the model are automatically used as edges for cut. If you don't want use them for cut, then you need to unmark them.

[ggaliens]

Were you able to stitch all three "triangle frames" together in one command ... or did you need to pick stitch three times ?

I can see some good potential for automation here. Thanks.

[micheus]

Were you able to stitch all three "triangle frames" together in one command ?

No. You can only select edges from two charts. But, by considering automation, maybe you can skip this by code. (I don't know if it is possible)

[dgud]

Kagehi first you must differentiate between uvmaps and textures.

Wings can only handle one set of uv-coordinates i.e. a uv-map, that means that
each (real) vertex can only have one uv-coordinate.

But wings can have multiple textures, you just make different materials and assign
different images to each material.

If you only want to work with a part of a uv-map select the faces you want to work with
and select uv-mapping.

I know LCSM generate bad maps sometimes, and I know the code is wrong but I don't know how to fix it the math is complex. Also blender got code/help from original inventor of the algorithm.

But yeah a lot of cool things could be done in Autouv as you say with normal baking and stuff, we need more programmers that can take a look at those things, I don't have time to do that.

[Kagehi]

Most of the issues I have had tend to be... long "bends". I.e., if making something like a Japanese bridge, and "slicing" the parts, even manually (and you definitely don't want to let Wings do this itself, in most cases), you get like a dozen segments that "should" line up, like -----, in a curve, but you end up with... a) it not being actually flat, at all, and b) often with parts "twisted over" each other. You can re-unwrap them, but then you often have to rearrange all the bits on the resulting map, to make room for it (since now its bigger than the unwrapper thought it should be, sometimes even "lapping over the edge" of the texture area).

When it works, it works... mostly OK. When it doesn't, it just goes nuts.

Ah, btw.. Never have worked out how you get a .beam file. This old thread, on the old site:

http://nendowingsmirai.yuku.com/topic/6707

The seventh article includes the "plugin" for baking normals, when generating textures, but either I have no idea how you actually install it (it definitely doesn't show up in the list of plugins when I look), or.. it has to be packed into a .beam somehow to work?

Frankly, I would just as soon do this with Wings 3D, if possible. Blender's interface drives me nuts (too many things you can't do with just a bloody drop menu, including anything involving evmap), and the online tool I found to trying to make things.. well, I sort of end up a different problem. It works, OK, if you have an image, like a bed of rocks, and you are not overly picky about it being exactly right. It.. doesn't work so well on "rendered" objects, which may have reflection/coloration effects which look good to the human eye, but which absolutely don't work right when trying to get a map off them. lol

Trying to get "extra geometry" for what needs to be a mostly "flat" object, basically, using normal maps. I will be importing the result into Second Life, and the more "detail", i.e. vertices, the higher the PE (prim equivalence) you end up with. So, a case, with gemstone it is, optimally, needs to be like 3-4 PE, at most, or a bookshelf the same, but if you actually put in "real" detail, using real surfaces, well.. the book shelf would probably end up being 20, or more PE, and the sales case.. would be even worse. :p

This is the whole core reason for wanting a more stable mapping - so its possible to create a low res object, and map the high res one a texture, to reduce the resource costs to something manageable when importing. lol With things.. a bit broken, and, apparently, this dandy plugin not being install-able anyway.. :p