Black Transparent Materials

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teamonster
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Joined: Thu Aug 16, 2007 7:36 am

Black Transparent Materials

Post by teamonster » Fri Mar 28, 2008 3:15 am

Hi,
I've had a problem with transparent materials.

I'm rendering an MP3 player with a transparent clip on the back.

I had a few other problems with materials but I've searched the forums and managed to nail them all down. I just have this one problem with the transparent clip on the back of the player.

It always renders as solid black. There was a thread where it was mentioned as having happened on the transparent face of a clock, but nobody replied to it.

Here is a list of things that I've done:
Highlighted all vertices and then Cntrl - N for recalculate normals outwards.
Recreated the material from scratch.
Created a new document and appended the player into that.
Tried diffuse and specular transparent materials.

Does anyone have any idea what is going on here?
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Cliprender_indigo_web.jpg
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Pinko5
Posts: 497
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Location: Italy

Post by Pinko5 » Fri Mar 28, 2008 3:23 am

Take a look to gain of trasparent material...
Luca. ;)
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GAIN.jpg
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teamonster
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Joined: Thu Aug 16, 2007 7:36 am

Post by teamonster » Fri Mar 28, 2008 5:37 am

Thanks Pinko5. I tried that, but its still doing it.

I found somewhere on the forums that there can be problems if the objects over lap. I've moved it apart and still no joy.

I've also applied all the rotations and scale. Still its black.

Has anyone any idea of how to change this?

Gog
Posts: 77
Joined: Thu Jan 25, 2007 10:35 pm

Post by Gog » Fri Mar 28, 2008 5:41 am

My first thought was the same as Pinko, try setting the gain to really low (say 1 or 2) as a test render?

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dougal2
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Post by dougal2 » Fri Mar 28, 2008 5:49 am

Have you checked that your mesh is entirely closed, has no holes or unwelded verts ?
try a "remove doubles" too.

teamonster
Posts: 8
Joined: Thu Aug 16, 2007 7:36 am

Post by teamonster » Fri Mar 28, 2008 7:41 am

Thanks for the help guys.

This one was really weird.

I had (about 6 times over creating the model) made sure the normals on clip were facing outwards. I even did the Cntrl N command on it about 4 times in the last day.

I went into to the edit window and hit the 'draw normals option'. Then I hit 'flip normals' and suddenly it turned into a pin cushion! :evil: :oops:

I love Blender, but this part of it annoys the stuffing out of me.

Thanks though for all your help.
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betternormals.jpg
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Pinko5
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Post by Pinko5 » Fri Mar 28, 2008 7:54 am

Congrats Tea... good work !!!
Luca. ;)

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Kram1032
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Location: Austria near Vienna

Post by Kram1032 » Fri Mar 28, 2008 9:21 am

For some reason, sometimes, Blender doesn't get the correct normal direction....
Then, you need to hit
Ctrl+Shit+N, to "flip them inward", which, in those cases, results in normals, flipped outward ;)

I think, it happens with concave shapes....

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alexmeyer
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Post by alexmeyer » Fri Mar 28, 2008 10:38 am

Could a mod please sticky this or any other thread about flipped normals and black transparent junk? Not a month goes by without someone asking what the heck happened to their renders.

If needed, I can write up a nice little post for stickification instead of using one of these threads.
From uncyclopedia.org, on "Elephant's Dream":

"The choice of the title is highly significant, because while the movie does not feature any elephants nor dreams, no one understands what happens anyway."

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Kram1032
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Location: Austria near Vienna

Post by Kram1032 » Fri Mar 28, 2008 10:51 am

not a week* ;)

Gog
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Post by Gog » Fri Mar 28, 2008 10:18 pm

Sure I said we should have 'Check your Normals' sticky a little while ago :)

teamonster
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Joined: Thu Aug 16, 2007 7:36 am

Post by teamonster » Sat Mar 29, 2008 12:18 am

That is why I was so annoyed. I had checked them and done the Recalculate Outside command about 6 times.

If you do put a sticky up, make it say "DOUBLE check your normals - even if Blender thinks its right"

The REAL reason Im so annoyed is that Ive run across this problem (normals that dont behave the way that they are told to) times when doing game models. I should have checked that. Its one of the things about Blender that drives me bananas.

Anyway, thanks for all the help.

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5OnIt
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Post by 5OnIt » Tue Apr 01, 2008 10:23 pm

I never trust my normals. Even if I recalculate outside I still select "Show Normals", zoom in, and then check all the faces. You'd be surprised at how many individual faces here and there don't get flipped.

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Kram1032
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Location: Austria near Vienna

Post by Kram1032 » Thu Apr 03, 2008 3:50 am

If you really want to confuse blender, try to make a single sided surface :twisted: - How should the normals be defined, there, in a correct way? ^^

HtechB
Posts: 4
Joined: Sun May 11, 2008 10:48 am

thanks dude!!!!!!!!!!!!!!!!!!!!!!!!

Post by HtechB » Tue May 13, 2008 10:25 am

Yes finally, I was making a mountain of the problem and researching all sorts of material setting bla bla bla when all I needed to do was check my normals. thanks teamonster

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