Overlapping vertices?
Author
Hi Gamedev! :DSo I'm using some existing models from other games for a PRIVATE mod im working on. But when i import them into blender or 3ds max the modeling software tells me it's got overlapping vertices. Is this normal with game models or is every vertex supposed to be welded?Kind regards!
Maybe. They might not be duplicates, it could be that there was additional information which was lost, such as two points that had different normal information or texture coordinates even though they're at the same position.It could be normal for that project, but no, in general duplicate verts, overlapping verts, degenerate triangles, and similar can cause rendering issues and are often flagged by tools. If it is something you extracted it might be the result of processing that took place rather than coming from the original, like a script that ends up stripping the non-duplicate information or that ends up traversing a mesh more than once.Most likely your warning is exactly the same one artists in the game would receive, and they just need to be welded, fused, or otherwise processed back into place.
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It's normal. Reasons to split a mesh edge of geometrically adjacent triangles are:Differing materials / textures / uv coordsEdge should show discontinutiy in lightinginstead smooth shadingDividing mesh into smaller pieces for fine grained cullingThus, splitting models and duplicating vertices is a post process necessary to use them in game engines, while artists keep the original models to do changes and for archivation.Turning such assets back to editable models requires welding with a tolerance of zero, or eventually a very small number. Issues might still remain.
Other things, e.g. the original cage of a subdivision model, or Nurbs control points, etc. can't be reconstructed that easily.
Author
Hi Guy's so i usually use this tutorial if i get overlapping:The reason im asking this is because: Does it matter if faces are welded or not if i convert them to meshlets like Nvidias asteroids? Or should they still be welded then?Does it matter how small/large the mesh is when welding by distance?Kind regards!
That is another “it depends on the details” question. There might be visual artifacts or not, depending on the details. There can be performance differences depending on the details. There are reasons to do it that we're already covered, a vertex can have far more than just position data which would make them different despite both being at the same location. There are details and choices beyond just the vertex positions overlapping.
Newgamemodder said:Does it matter if faces are welded or not if i convert them to meshlets like Nvidias asteroids?Usually no. You need to regenerate the meshlets anyway after editing a model. It's done by a preprocessing tool, and the usual asset pipeline is: Model from artist → automated tool to split edges where needed to get one mesh per material, compute meshlet clusters, quantization for compression, reorder vertices for cache efficiency, etc → save as asset to ship with the game.So meshlets do not add to the risks from welding vertices which you already have. Artwork is not affected from meshlets in general.However, this applies to games production, not to modding. Things like Nanite and meshlets ofc. make it even harder to mod existing assets, since modders don't have those automated preprocessing tools if devs don't provide them.Newgamemodder said:Does it matter how small/large the mesh is when welding by distance?Yes. Usually you give a distance threshold for the welding, so the scale of the model matters.
My advise is to use the smallest threshold possible and observing UVs, which should not change from the welding operation.
#overlapping #verticesOverlapping vertices?
Author
Hi Gamedev! :DSo I'm using some existing models from other games for a PRIVATE mod im working on. But when i import them into blender or 3ds max the modeling software tells me it's got overlapping vertices. Is this normal with game models or is every vertex supposed to be welded?Kind regards!
Maybe. They might not be duplicates, it could be that there was additional information which was lost, such as two points that had different normal information or texture coordinates even though they're at the same position.It could be normal for that project, but no, in general duplicate verts, overlapping verts, degenerate triangles, and similar can cause rendering issues and are often flagged by tools. If it is something you extracted it might be the result of processing that took place rather than coming from the original, like a script that ends up stripping the non-duplicate information or that ends up traversing a mesh more than once.Most likely your warning is exactly the same one artists in the game would receive, and they just need to be welded, fused, or otherwise processed back into place.
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It's normal. Reasons to split a mesh edge of geometrically adjacent triangles are:Differing materials / textures / uv coordsEdge should show discontinutiy in lightinginstead smooth shadingDividing mesh into smaller pieces for fine grained cullingThus, splitting models and duplicating vertices is a post process necessary to use them in game engines, while artists keep the original models to do changes and for archivation.Turning such assets back to editable models requires welding with a tolerance of zero, or eventually a very small number. Issues might still remain.
Other things, e.g. the original cage of a subdivision model, or Nurbs control points, etc. can't be reconstructed that easily.
Author
Hi Guy's so i usually use this tutorial if i get overlapping:The reason im asking this is because: Does it matter if faces are welded or not if i convert them to meshlets like Nvidias asteroids? Or should they still be welded then?Does it matter how small/large the mesh is when welding by distance?Kind regards!
That is another “it depends on the details” question. There might be visual artifacts or not, depending on the details. There can be performance differences depending on the details. There are reasons to do it that we're already covered, a vertex can have far more than just position data which would make them different despite both being at the same location. There are details and choices beyond just the vertex positions overlapping.
Newgamemodder said:Does it matter if faces are welded or not if i convert them to meshlets like Nvidias asteroids?Usually no. You need to regenerate the meshlets anyway after editing a model. It's done by a preprocessing tool, and the usual asset pipeline is: Model from artist → automated tool to split edges where needed to get one mesh per material, compute meshlet clusters, quantization for compression, reorder vertices for cache efficiency, etc → save as asset to ship with the game.So meshlets do not add to the risks from welding vertices which you already have. Artwork is not affected from meshlets in general.However, this applies to games production, not to modding. Things like Nanite and meshlets ofc. make it even harder to mod existing assets, since modders don't have those automated preprocessing tools if devs don't provide them.Newgamemodder said:Does it matter how small/large the mesh is when welding by distance?Yes. Usually you give a distance threshold for the welding, so the scale of the model matters.
My advise is to use the smallest threshold possible and observing UVs, which should not change from the welding operation.
#overlapping #vertices
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