Connected vs unconnected vertices

Ran_TH

Is there any difference in output or runtime performance when the mesh has unconnected vertices?

CAMA

I think, yes.

Ran_TH

Thank you, @CAMA, interesting finding.
I can't see it clearly in the GIF, but does both artmesh has similar mesh lines?

Also I want to know if unconnected vertices affect the output as well, like whether it will have any effect to the mesh rendering in the SDK.

Live2D manual doesn't really specify why we have to connect the vertices, nor why "Auto Connect" button exists.

CAMA

I can't see it clearly in the GIF, but does both artmesh has similar mesh lines

Look closely, blue with unconnected vertices and red with connected vertices, but in a different way.

Also I want to know if unconnected vertices affect the output as well, like whether it will have any effect to the mesh rendering in the SDK.

Man, you already have a different output in Live2D, of course you will have it in the SDK.
If you make an artmesh of any shape, Live2D will divide it into triangles in its own way, because the SDK can only work with triangles. And automatic connections are often different from what you can do yourself, so you will get a different result.

Ran_TH

Yeah I can see it now that both has different topology so the varying result can be expected.

But let's say we connect some vertices in the first blue mesh so both mesh has similar topo, would it matter if the rest are unconnected?

CAMA

But let's say we connect some vertices in the first blue mesh so both mesh has similar topo, would it matter if the rest are unconnected?

No. The result will be identical as on the red mesh.

Ran_TH

Great, so I suppose visually connecting the mesh doesn't matter too much as long you are giving it correct geometries. But at that point I guess you'll just want to connect them all..

Thanks for taking your time for making all these demo.

CAMA

You're welcome!

Tak.W(Staff)

@Ran_TH @CAMA

Hello!
Thank you for always using our products.

We have researched this agenda.

As a conclusion, there is no difference in the run-time drawing load when all the vertices of a mesh are connected or when only some of them are connected.

Cubism Core uses `csmGetDrawableIndexCounts` and `csmGetDrawableIndices` to get information about the polygons to draw, and this does not change.

However, we recognize that a model in which all mesh vertices are not connected is not a correct Live2D model.
We want you to connect all the vertices of the mesh when you create your Live2D model.

We will work with the Editor team to investigate the pros and cons of this approach.

Ran_TH

Tak.W(Staff) said:

@Ran_TH @CAMA
However, we recognize that a model in which all mesh vertices are not connected is not a correct Live2D model.
We want you to connect all the vertices of the mesh when you create your Live2D model.

We will work with the Editor team to investigate the pros and cons of this approach.

Thank you for your response! @Tak.W(Staff)

In the community there has been some consensus about people leaving the vertices unconnected. Connected vertices are seen to obstruct texture view and also on manual mesh edit erasing the connected lines is seen as a hassle, so having a 'hollow' unconnected mesh is becoming kind of a norm because there's no difference in export anyway.

I'm just interested to know what Live2D devs say about it, probably you can come up with something that improves user experience on that front