Mesh becomes transparent?

[TheMadAlice03]

Hey everyone!

So, I'm running into a bit of an issue here. And it seems to happen to a few of my creations (and not only)

I'm importing my DAE into  SL, and parts of the mesh become transparent even though they exist and you can see them from a different angle.

Here is a gif of my issue: https://gyazo.com/ba80a1fea94cda4dae1efc3cbd319c45

The inside of the jacket is transparent even though the jacket has an inside.

I'm not sure what I'm doing wrong? I used to think it's something with the alpha of my mesh body overlapping but if I rezz the original object same thing happens, even worse, you can't even see the back: https://gyazo.com/8c28ecbe65379f6bba96ba2e367cd297

 

If anyone can help me figure out what's happening, I'd be more than grateful.

Thank you kindly!

[Callum Meriman]

The inside normals are back to front.

I assume you are using blender? Go into edit, then select all the inside faces, then Mesh>Normals>Flip Normals

You may find it useful to press N, scroll down and tick backface culling so it's more obvious as you are meshing.

[TheMadAlice03]

16 hours ago, Callum Meriman said:

The inside normals are back to front.

I assume you are using blender? Go into edit, then select all the inside faces, then Mesh>Normals>Flip Normals

You may find it useful to press N, scroll down and tick backface culling so it's more obvious as you are meshing.

Thank you!!

[Macrocosm Draegonne]

I sometimes get this issue too in a different context.   if I do a solidify modifier, with zero thickness, and open ends, it places the mesh in the exact same location but flipped the other way, this is similar to a duplicate flip and join.  Sometimes when uploading though a ton of the faces and verts will disappear, even though the normals are correct.  I suspect that SL is culling them because the verts are in the same location?

[ChinRey]

1 hour ago, Macrocosm Draegonne said:

I sometimes get this issue too in a different context.   if I do a solidify modifier, with zero thickness, and open ends, it places the mesh in the exact same location but flipped the other way, this is similar to a duplicate flip and join.

I think it's called "lammelled polys" or something like that and they cause serious problems not only for SL but for 3D applications in general so they should be avoided. Never have two polys sharing exactly the same set of vertices.

A bit off topic but this reminds me of one LI saving tip I haven't posted here for a while: In Blender, never use modifiers to alter the mesh geometry. Go to edit mode and get up close and personal with your vertices. They appreciate it and will reward you with lower LI and more efficient mesh.

[Macrocosm Draegonne]

9 minutes ago, ChinRey said:

I think it's called "lammelled polys" or something like that and they cause serious problems not only for SL but for 3D applications in general so they should be avoided. Never have two polys sharing exactly the same set of vertices.

A bit off topic but this reminds me of one LI saving tip I haven't posted here for a while: In Blender, never use modifiers to alter the mesh geometry. Go to edit mode and get up close and personal with your vertices. They appreciate it and will reward you with lower LI and more efficient mesh.

well they do have their own vertices, but they're in the same location as the front facing side.  Is that still going to cause the same issue?  Does the uploader cull vertices if they're in the same location but have opposing normals?  I know it doesnt the other way for onion skin, but maybe the flipped normals cause the culling.

EIDT:  This was happening with a two sided plant mesh, I ended up putting a 1mm thickness to separate the front and back, and the uploader was much happier it seemed.

So the solidify is not good for a two sided plant plane?  I will test the copy and join method then, its easy enough, I saw solidify mentioned here in the forums several places as the best way to  get the back side of the mesh visible so thats why I was working it that way..

Edited October 11, 2018 by Macrocosm Draegonne

[ChinRey]

1 minute ago, Macrocosm Draegonne said:

Does the uploader cull vertices if they're in the same location?

No, it doesn't.

Are you sure you always remember to apply the modifer before exporting?

In any case, the quick, easy and (relatively) efficient way to emulate backfaces in SL is select the faces (in edit mode), duplicate (*****+D) and flip the normals (Ctrl+F - on top of the menu).

[Macrocosm Draegonne]

1 minute ago, ChinRey said:

No, it doesn't.

Are you sure you always remember to apply the modifer before exporting?

In any case, the quick, easy and (relatively) efficient way to emulate backfaces in SL is select the faces (in edit mode), duplicate (*****+D) and flip the normals (Ctrl+F - on top of the menu).

perhaps that was it, I did test both ways, letting the exporter finalize all the modifiers seemed to work alright, but it was inconsistent, a few times I lost half the vertices when importing but it seemed more related to having the front and back in the same location. Hahaa, well there ya go, I love learning new useful things!  thanks for the pointers & excellent posts here in the forums.