Some objects turn black no matter material properties

[Luc]

Hi everyone !
I'm new to Indigo and 3d modeling and I have a lot of problems
But there is especially one that is really annoying :

I'm currently modeling a seringe so I have to make a tube made of glass.
At first everything is okay, the render of the tube is really good, but after adding some new pieces, my tube now renders black (like an alpha matte).
I tried changing materials, even using materials of other objects of the scene that work good, but so far, none of this worked...
I even tried to use a material from the matDB, still black.
Finally I re-started from scratch, but the new tube also render black.

If you have an idea of where my problem could be.

[fused]

check your normals. they have to point outwards.

[Pinko5]

Have you control the face normal??? Go to edit mode select all faces of the black object with (A) then CTRL+N...... try to render again...
ciao
Luca.

[Luc]

Just checked the normals, but no change...

It rendered fine just now, no apparent reason as I didn't touch anything...
I tried to render again without touching anything and it rendered black once again.

I hope there would be a way to have more stable results

[MSUdom5]

Glass takes a little while to get the hang of. Still sounds to me like a normals problem. Could you post a picture or two of your problem?

[Luc]

This is not a normal problem, because I tried to add->mesh->cylinder and it was black too (I don't it could have normal problems)...
The problem doesn't always occur, it seems to occur for no apparent reason.

Quite strange.

[MSUdom5]

Interesting... Could you zip and post your .blend file? I'd be happy to take a look at it.

EDIT: If the two meshes are intersecting each other, it could be a precedence issue.

[Luc]

Precedence it is ! ^^

Thanks for the help everyone !

[MSUdom5]

Looks great!!

[Kram1032]

I still hate syringes

Great model, anyway