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Hoew to render a nice glass of wine ?

Posted: Thu May 22, 2008 12:10 pm
by Gwenouille
Hello !

While i am not completely a noob with Blender, i am new to Indigo.
I've played a bit with 0.7 and 0.8, but not seriously.

I have the following problem with the latest 1.09 and its Blendigo:

Image

I've modelled this simple scene to test and learn Indigo.
You can see 2 glasses and floating wine (Woww!)

The pb is that, while hovering smoothly into the warm air of a nice spring evening, the wine is a nice ruby color (far right). BUT as soon as you put it in the glass (left) , it looses it's color and turns to vodka ! While this might have some advantages, it is not meant to happen, is it ?

The wine is too big for the glass so to speak, it goes right thrue the glass material, as i read it in an indigo pdf somewhere...

Someone has a clue ?

Wine has an absorbtion gain of 12 and an IOR of 1.33

Posted: Thu May 22, 2008 1:31 pm
by zsouthboy
Precedence of glass must be > precedence of wine

Posted: Fri May 23, 2008 12:32 am
by PureSpider
(the wine must intersect with the glass a tiny bit and) the precedence of the glass must be greater than the precedence of the wine
let us see your results ;)

Posted: Fri May 23, 2008 1:34 am
by Gwenouille
Hello.
Thanks for your help !
What do you mean with precedence ? I've made the wine smaller so that it doesn't touch the glass and it seems to work, but it goes against what is sais in the indigo manual.
I guess i should find out what "precedence" is !

Here is what i get with no overlapping of the meshes:
Should i lift the glass of the ground even more ?

Image

Posted: Fri May 23, 2008 1:35 am
by BbB
Also, your glasses seem to intersect with the tablecloth, which in Indigo, as in life generally, is not a good thing.

Posted: Fri May 23, 2008 2:03 am
by Gwenouille
Mmmm they don't: about 0.00003 Blender Unit.
I guess this wasn't enough :oops: I've lifted them a bit more

(I like this kind of humour by the way !)

Thanks for the "precedence" tip: I've found it in the exporter and it works.

Now i need to learn how do smooth these caustics...
Image

Posted: Fri May 23, 2008 2:11 am
by Zom-B
Hey Gwen, the black Ring is maybe a normal smoothing Issue. Try to subdivide the mesh more often on the Edges to prevent this!

For some smoother Caustics Rendering MLT + BiDir seems the best way.
You also could simply to a second render Region Image where you only render the area of the Two glasses, so Indigo will use its full render Power only at this part of the image for better/faster convergence on the caustics...
finaly you combine the big rendering with your renderRegion one (for such techniques Reinhard Tonemapping is a no-go, use linear or camera tonemapping instead!)

Posted: Fri May 23, 2008 3:08 am
by CTZn
about 0.00003 Blender Unit.
Well that's less than

Code: Select all

"ray_origin_nudge_distance" "0.0001"
so rays may get killed here. Either disminish nudge distance (advanced manip) or set distance strictly superior to 0.0001 units.

As for the wine issue I don't see how precedence impacts on material aspect.

Precedence tells wich volume overlaps wich when they intersects. Smaller value = on top of bigger values.