Polygons sharing edges

ChrisInTheBox

I don't know if this is a good practice, but can more than two faces share an edge? Like in this picture-



I've tried doing something like that for one of my models, because there are only a few faces that need to overhang from an edge. Normally I would make a plane as a separate object and snap the vertices to the other object, but would it still work if they are actually merged together with the object?

One thing I notice is that the normals start acting screwy and the program doesn't know which way they should align, so one edge of the face appears very dark.

pior

boooo baaaad diiiie!

Mark Dygert

Attaching them is normally bad and causes the universe to implode.

Psyk0

Yeh dont temper with the fabric of the universe kid .

EarthQuake

You'll get pretty screwed up smoothing if you do stuff like that.

ChrisInTheBox

So far that's a unanimous NO. Okay, looks like I'll just make a separate object and just snap it to the other object's vertices.

MoP

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Okay, looks like I'll just make a separate object and just snap it to the other object's vertices.

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Yep, that's the best solution.

pior

And edit the normals! It's super powerful if your engine supports it (Unreal2 will recalculate the normals on import hence screws the hand edited ones for instance)

Eric Chadwick

Some engines hate this because of their shadow methods or collision-hulls or LOD.

But for us it's not a problem. It actually makes things slightly easier when the model uses bones, since we're weighting two verts there instead of four. Also helps if precision is low in the 3d app, since welded verts share the same xyz coords, instead of being separated and possibly diverging. 3ds Max sucks for precision sometimes.

When the planes use different normals (via edited normals, or via smoothing groups) then most engines count them as four separate verts anyhow.