Probleme with objects transpary without backgroung in Arnold

[ejpaul]

I use SkydomeLight. Il put the camera to 0 in order to render without backgound. When rendered, avery transparent objet is opaque, no transparency. can some one help ?

[mspeer]

Hi!

Screenshot please.

[ejpaul]

red cross in the glass. should be transparentred cross in the glass. should be transparent. the opaque attribute of The glass objet is unchecked.

I tryed this with many other simple  scenes, I incounter the same problems ! Try render  a single glass, without backgroung when u use the skydome light, same problem. Where there is hole it is ok, but objets with tranparency are not

thanks

[mspeer]

Hi!

Every solid object will create a white Alpha channel regardless of transparency, that's correct.

(You still have reflections and refractions with a transparent object.)

Use Render Layers or AOV ID for alpha instead.

(Keep in mind that in compositing it may look wrong because of missing reflections and refractions then.)

Composite transparent objects is not as easy as you might think.

[ejpaul]

Ok thanks for ur help. I'll try AOVs today.  But this works perfectly with Mental Ray Maya 2017.

Please if possible, try to render a simple water glass without background, using Arnold. Help me if U get it.

Thanks again . Sorry for my poor English.

[mspeer]

Hi!

With Mental Ray it worked also only in some rare cases.

Compositing of transparent objects is also far more complex then you might think of.