What, exactly, is “welding?”

rames44

I’ve seen discussions of clothing not working with dForce because “seams aren’t welded.” I understand, conceptually, the issue - if a pocket, say, is to be simulated as part of a garment, it must actually be connected to the garment. If it isn’t, of course it’s going to fall off. As Robin Williams said in one of his routines, “Oh, ****, gravity works!”

But is “welding” a specific operation? Can one take a garment that has such an issue and “weld” the parts together? And if so, how? Or is this just modeling nomenclature for “these two surfaces share the same vertices?”

Richard Haseltine

No, welding just means that where the two pieces of mesh meet they share vertices, rather than having disconnected vertices. The command in a modeller to merge two vertices in the same place (or to move them together and merge them) may well be called Weld of course.

mindsong

Note that in most modelling programs, such a vertex weld - to enable dyamic clothing to work better (not just dforce) - will 'unbind' the mesh from its existing UV texture maps (they no longer work), and you'll have to generate new UV maps and texture the mesh again (all vendor UVs are no longer meaningful after the weld). You could do this retexturing in most modellers or a dedicated UV-Mapping program. It's an art in its own right.

I'm still trying to find a good/easy/cheap way to weld such verticies and preserve the original UV maps (e.g. clothes).

Anyone find such a trick?

cheers,

--ms

frank0314

You can do it in a mapping program such as UVLayout or others by making your seam along that welded section. You just select the polies you want to cut and do it. It will still be connected on the model.

mindsong

frank0314 said:

You can do it in a mapping program such as UVLayout or others by making your seam along that welded section. You just select the polies you want to cut and do it. It will still be connected on the model.

Thanks for the reply,

Hmm, so you can load up the mesh (e.g. obj) with the existing/original UVs, and there's a mesh/UV action that you can take to 'weld' the mesh polys at a (any) existing UV seam, and save it, and the original textures and all other textures that worked on that original mesh/UV will continue to work?

That's sounds exactly like what I've been looking for.

Do you think this would work with buttons/pockets/belt-loops, where it's not really like a 'top-of-the-shoulder' seam where the front and back of an outfit come together?

Such a trick to weld hair strips to a skull-cap would have obvious value if the original UVs conitnued to be useful.

I assume, in all cases, that adding or removing points (vs moving/welding near-poiints together) is still a no-no...?

cheers,

--ms

Inkubo

Blender will keep the UVs if you remember to go into each object and ensure the associated UV map has the same name. When the UV maps are named differently, Blender discards one upon welding; when they are named the same, all the UV information is kept. Welding geografts works just fine in Blender, but I haven't messed with dForce yet so I've had no need to attempt welding detached bits of clothing. I don't expect that to work any differently, though.

Richard Haseltine

mod will preserve UVs and morphs (if loaded as morph vertex maps) too, but yes it is a potentially risky operation. You can also, I believe, use dForce Add-Ons to link separate parts though I'm still hazy on the details (there is some information in the dForce Start Here thread).

mindsong

Richard Haseltine said:

mod will preserve UVs and morphs (if loaded as morph vertex maps) too, but yes it is a potentially risky operation. You can also, I believe, use dForce Add-Ons to link separate parts though I'm still hazy on the details (there is some information in the dForce Start Here thread).

I assume you meant 'modo'? (thanks for that tip). As for being risky, any radical change on one part logically has to have an impact on the other, so that's not surprising. In fact, keeping it all intact is the impressive accomplishment!

I saw sickle-yield's video on mapping/painting for dforce, but have not seen anything regarding your mentioned 'Add-Ons'. I'll go look at the 'Start-Here' thread you mentioned (thanks). Maybe this can all be done in place (DS) now... That would be quite handy!

cheers,

--ms

mindsong

Inkubo said:

Blender will keep the UVs if you remember to go into each object and ensure the associated UV map has the same name. When the UV maps are named differently, Blender discards one upon welding; when they are named the same, all the UV information is kept.

Ok, neat. so - in Blender, you load your obj(s), you rename each UV to be the same as its obj, make the welds (neither adding or removing any other points), then rename the UVs back (if you wish) and save? Or am I missing something?

Inkubo said:

Welding geografts works just fine in Blender, but I haven't messed with dForce yet so I've had no need to attempt welding detached bits of clothing. I don't expect that to work any differently, though.

I could see how that would save a lot of grief for geograft users. Will save that tip for future reference!

cheers,

--ms

Inkubo

mindsong said:

Ok, neat. so - in Blender, you load your obj(s), you rename each UV to be the same as its obj, make the welds (neither adding or removing any other points), then rename the UVs back (if you wish) and save? Or am I missing something?

 

In general, it sounds like you got it... The UVs literally must have the same name. So if you are welding headtails to a Lekkulion, you'd go into each object's UV map and rename it to "uvmap" (for example) so the two obj's maps will be merged when the vertices are welded. Then Join the objects so Blender will let you select the pairs of vertices to weld, then you go around and weld each pair. (I always select the main-body vert second, look up to the top of the screen to verify that the stats bar shows only 2 verts selected, then press Alt-M and choose "At Last" to bring the geograft mesh's vertex into line with the main body mesh. Of course the geografted part must be fitted to the main body in the first place, when you export from DS, so the majority of vertices are already in the proper locations.)

You can save the welded mesh, but then once you import it back into DS, it's just an OBJ mesh. I'm not sure if there's a way to transplant skeletons so the final, welded product will become a posable character again. (But if there is a way do do that, to weld parts, transplant the skeleton, and end up with a fully posable character, I'd like to learn!)

mindsong

Great detail. thread saved/PDF-d for future reference.

Thanks so much for going into that detail for me/us. Let me hack through this before asking any more questions. It looks like things should make sense when I get there!

cheers,

--ms