Ultimate Unwrap 3D help

Community Forums/Developer Stations/Ultimate Unwrap 3D help

big10p(Posted 2004) [#1]

I have a mesh with a section of tris all connected in a row. I simply want to weld all the verts in this 'strip' of tris but I can't seem to get UU3D to do it properly. Using the 'weld vertices' command, it reports that 0 verts were welded. :/ Why won't it weld my verts?

Also, could someone explain exactly what the difference between welding vertices, faces and UVs is in UU3D? I'm so confused and frustrated with this. :P

ashmantle(Posted 2004) [#2]
I imagine that it wouldn't weld tris that belongs to a different faces group.. check that the vertices share the same "surface" before welding..

Bob3d(Posted 2004) [#3]

there are 2 different type of welds.

1)welding 3d
2)welding 2d uvs.

welding 3d is very useful for when ie a model got some vertices unwelded in export. Some sofwares don't understand well smoothing or uv sharing etc, and duplicate vertices in certain places, producing geometry seams, unwelded stuff.

You can weld faces or vertices. Faces, I never actually checked, but I prefer to use only work on weld vertices. I think weld faces will also weld small faces, which I totally avoid. Also, the typical problem is always solved with just weld vertices.

The second type of weld, is for what u're aiming. Welding UVs and is on the 2d menu, not in 3d one.

If , for example, u want to weld a bunch of faces, but not weld together into a single dot, you needda play with the threshold number of weld uv dialog. Usually is at 0.01, which uses to work, but often you need a bit of trial and error more.

I sometimes need to do a work of be continuously sewing verts, and then set (u can totally customize every key shortcut in UU (Menu Options/Hotkeys)) the same shortcut I have at metasequoia : ctrl+J . And set first time a huge value, 12, or so. So that it'll weld the verts no matter the far they are. Thedialog remembers the last value allways, so this method rocks for quick sewing.I'd like an option for not show the dialog in this case...

But when u want to sew only the almost coincident in position verts, use small values, but sometimes like probably in your case, it is too small and it does not weld a thing. So, just trigger weldUVs again, and try a different value, till u see it works as u want. If u have a sharp eye, u'll see how some lines that did seem thicker or double, will become only one.And once u get very used to it, u learn to see which was not welded; even more, how to avoid some verts distanced, just moving closer together before welding.

Long explanation, but lately I don't know if the language barrier is allowing me understand the questions... :?

Bob3d(Posted 2004) [#4]
and in UU it can weld uv verts that are in different groups...

ashmantle(Posted 2004) [#5]
ok, thanks for clearing that up ^^

big10p(Posted 2004) [#6]
AshMantle: The mesh is single surface (1 texture) and the tris share the same group.

Bob3D: Thanks for trying to explain things but I think my problem comes down to me not knowing exactly what welding UVs does and what it's used for. :P

I understand that the 3D welding of verts actually affects the geometry but UV welding has me a bit stumped. When you say:
The second type of weld, is for what u're aiming.
I don't understand what you mean. :/

I don't even think UV welding is related to my problem, TBH. Let me explain with a simple example:

(pic 1) Here are 2 strips that I want to use the same area of texture because they are the same size/shape. I do this by copying the UVs from one strip and pasting them onto the other.

(pic2) Here's the result which 'looks' exactly how I want but some of the tris have become unwelded...

(pic 3) I've packed the UVs here (using 'separate by connectivity') just to prove that some tris have become unwelded.

It seems the operation of copying and pasting the UVs from one strip to the other has broken up some tris. I don't understand why. I have also verified this in Blitz3D itself: I have a prog that lets me pull the verts of a mesh apart.

Can you - or anyone - shed any light? :)

Bob3d(Posted 2004) [#7]
what you need to fix it anyway is weldUV tool.

-Do a rectangle selection catching it all

-with that selected, go to "2D tools" menu. "Weld UVs" write in the dialog box now a threshold for it. you would need to zoom a lot on the verts u think its unwelded and see if it changes from a think or double line, to a single one. As if u just mover the vertex, it'll move unwelded, freely, as is the way Lith and UU work, at vertex level all is unwelded when u handle it with move tool. But if u don't do so, and apply "weld uvs", the uvs will remain welded as u want.

-if what u're asking is the actual mesh, in 3d, is unwelded at those verts, in UU it is so: position them exactly as u want em match (as u already did before pack) hit in "3d tools" menu, "weld vertices" with enough threhold to weld the coincident verts, but no as huge as to connect unwated ones.

The difference is if u're talking bout mesh broken in 3d, verts unwelded phisically, or just uvs unwelded.

Weld uvs is acting on the UV mapping coords info of the mesh, not in the 3d vertices on teh "real 3d thing" .Though is quite unaccurate to speak so..

big10p(Posted 2004) [#8]
The difference is if u're talking bout mesh broken in 3d, verts unwelded phisically, or just uvs unwelded.

Yes, I'm talking about the actual 3D verts of triangles in the geometry are becoming unwelded. Using an increased threshold when trying to weld them back together still doesn't work - 0 verts get welded! :/

I really don't know what's going on. Why are the triangles getting separated by the copy/paste operation, in the first place?


big10p(Posted 2004) [#9]
OK, I've contacted the author of UU3D about my problem and this is his response, in case it's of use to anyone else:


There's two main menu options in Unwrap3D, 2D Tools and 3D Tools. 2D Tools will only modify UV coordinates, they don't touch geometry. While all commands under 3D Tools modify geometry, they don't touch UV coordinates.

On the subject of welding UV coordinates, actually, no UV coordinates can be welded or unwelded in Unwrap3D (internally speaking). As you probably noticed, you can select a single UV face and drag it anywhere, so it is never connected in any sense.
Internally in Unwrap3D, all faces have their own UV coordinates, so this is why the program behaves the way it does. It was initially designed like this, because it simplified UV mapping for many things.

When you do a 'Weld UVs' in Unwrap3D, this command will only move UV coordinates to nearby UV coordinates that are within tolerance range. Nothing is physically welded.

When you do a 'Pack UVs' separated by connectivity in Unwrap3D, this command needs to build an edge structure from the UV coordinates as they are shown on screen. So if you have overlapping UV coordinates, this may confuse the edge building process.
This command only works well when you have UV coordinates that are not overlapping.

As for the welding/unwelded of geometry, this should work as expected.
Vertices are internally welded. You can easily see the effect of welding vertices by switching to a Smooth-shaded rendering mode. After vertices are welded, the hard edges are replaced with smooth edges. And if you try to select a face in 3D and move it, you will know it is connected by the fact that it doesn't break off from the rest of the geometry.

But, back to your problem. What I would suggest in your case if you want to move one set of UV coordinates to another, and align it exactly, is to use the numerical Move UVs option, e.g. Edit | Move | Arbitrary. First, move one set 'absolutely' to UV coordinate 0,0. Then move the other set 'absolutely' to UV coordinate 0,0.
Now, both sets should be aligned exactly on top of each other. You can now select both sets and drag them anywhere you want.

I hope some of that was helpful.

Brad Bolthouse

Bob3d(Posted 2004) [#10]
sorry, missed this thread again.

you can just...do not use the pack function, and organize the UVs yourself, or easier, if you want to just have to identical straps, instead of mirroring one and relocate it exactly over the other, just do a planar/one sided. And choose the axe direction (for front, side view, etc)

or...do a camera map, setting in the 3d view the angle you want, or a fron, left, top view, etc. the 3d window must be selected for this.(and then , 2d tools/uv mapping/camera)

Both ways map one strap over the other.

But i wouldn't use pack function. I don't use untangle or relax either...getting th egood values takes me teh same time than doing stuff by hand like always :D

big10p(Posted 2004) [#11]
I'm not using the pack function with overlapping UVs anymore as Brad (the author) explains above, it can cause problems.

Sorry, I don't see how I would get planar mapping to map 2 strips on top of each other; besides the 2 strips can be on different planes.

Camera mapping I haven't used - I'll have to experiment with that.

Anyway, today I actually managed to get things to work the way I want! :)

I used Brad's suggestion to map the strips on top of each other. Then I had to do some additional vertex/UV welding and everything seems to be OK - i.e. no unnecessary unwelded tris! Phew, it's taken me ages to sort out that prob.