calculating clean normals in meshes with duplicate vertices

[zillion42]

Hi,

well, basically, can it be done ? I spent a good part of the day finding a method to remove duplicate vertices faster than

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->getMeshManipulator()->createMeshWelded

which seems pretty O(n²) brute force to me, but I guess there is no other way...

The problem is that for a terrain kind of mesh basically the method

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for (u32 i=0; i<currentIndices->size(); i+=3) 
		{
			u32 index1 = currentIndices->operator[](i+0);
			u32 index2 = currentIndices->operator[](i+1);
			u32 index3 = currentIndices->operator[](i+2);

			const core::vector3df normal = core::plane3d<f32>(currentVertices->operator[](index1).Pos,
															  currentVertices->operator[](index2).Pos,
															  currentVertices->operator[](index3).Pos).Normal;
			
			currentVertices->operator[](index1).Normal += normal;
			currentVertices->operator[](index2).Normal += normal; 
			currentVertices->operator[](index3).Normal += normal;
		}

would work just fine, if triangles would share vertices. But since that is not the case it can't ever work since most tri's have their own friggin 3 vertices, and the normal vector cant be added together for the unshared planes.
If you turn on debug data normals you can see 2 normals sticking out of each vertice... Maybe I'm just little overworked and tired, but I dont see the light here...

Thx in advance...

[hendu]

If brute force fails, add more cores That loop looks like it would parallelize really easily with openmp, so you could get a nice speedup on a quad.

[zillion42]

oh god, I divided my icosahedron to level 9, which actually even renders with about 0.2 fps, of course it will never need to render as a whole later, but because it takes so long to generate I thought write it to file...

now I'm waiting for quite some time already and the filesize has just passed 420 MB

going to edit this post and report final size...

But in fact, generating takes considerable less time than writing
and needless to say that welding points in that mesh will never finish...

EDIT:
filesize has just exceeded total ram usage with windows...
EDIT2:
ok final stat and a good laugh... sorry been definitely working to long

Size on Disk: 1,05 GB (1.137.520.640 bytes)

going to drink some beer now...
EDIT3:
I've spent some time with exporting various small and big models now in irrmesh and obj format. To the result that none of the obj's was ever readable by maya and none of the objects in general was readable again by irrlicht...

and back to the original question... does anyone know a way to make meshes with duplicate vertices smooth in the sense of properly calculating normals ?

[Mikhail9]

...because it takes so long to generate I thought write it to file... But in fact, generating takes considerable less time than writing

Been there, learned that. It's always a surprise, but sometimes caching just doesn't help.

You're working a hard problem. Please share the solution if you find one.