I guess im confuse on what you mean by "welded"
For quite some time, I've been thinking about creating a CSG editor without the use of a BSP algorithm( Maplet uses a BSP algorithm for it's CSG if I remmember right). Anyways, It comes down to finding what polygons of the mesh are effected. Then you would have to recreate it with new polygons to create the combined mesh you want out of the CSG operation you've made.
When it comes down to "welding vertices", I think of multiple polygons sharing a similar vertex. If that is what you are thinking of, well ... think about how the uv cords of a specifc vertex would effect texturing of multiple polygons that share it. On paper, draw two squares side by side representing "walls". Map uv values for each point of one wall and then try to map uv values on the wall that's next to it. For a basic example... to have the same texture mapped to each wall looking the same, then the two vertex points that share the same location between the two walls cannot be welded( or be used by each wall ). I would not worry about welding vertices until the mesh was ready to be exported for use in a game.
I know decorator has a welding function to optimize the mesh, but my mind is not complicated enough yet to understand what conditions decorator uses to weld vertices togethor without effecting texturing.
Anyways, just my humble thoughts. Hopefully that helped some how and not totally useless. :)
For quite some time, I've been thinking about creating a CSG editor without the use of a BSP algorithm( Maplet uses a BSP algorithm for it's CSG if I remmember right). Anyways, It comes down to finding what polygons of the mesh are effected. Then you would have to recreate it with new polygons to create the combined mesh you want out of the CSG operation you've made.
When it comes down to "welding vertices", I think of multiple polygons sharing a similar vertex. If that is what you are thinking of, well ... think about how the uv cords of a specifc vertex would effect texturing of multiple polygons that share it. On paper, draw two squares side by side representing "walls". Map uv values for each point of one wall and then try to map uv values on the wall that's next to it. For a basic example... to have the same texture mapped to each wall looking the same, then the two vertex points that share the same location between the two walls cannot be welded( or be used by each wall ). I would not worry about welding vertices until the mesh was ready to be exported for use in a game.
I know decorator has a welding function to optimize the mesh, but my mind is not complicated enough yet to understand what conditions decorator uses to weld vertices togethor without effecting texturing.
Anyways, just my humble thoughts. Hopefully that helped some how and not totally useless. :)