i try to setup a glass material, what am i doing wrong?

[andi]

Hello first of all, great program! Something i was looking for, an unbiased physically exact renderer.
Currently i'm playing around with the demo version.
Now to the glass:
In fact setting up glass (specular material) works as i expected it beside that light seems not like to travel through it. Only if the next thing it hits is the camera.
To be more clear, i can see through it, but it casts shadows as any other solid material. It doesn't matter what value i choose for diffuse, reflection, index or even opacity.
Am I doing something wrong? Is Octane doing something wrong?

thanks in advance!
andi

[matej]

Light not passing through transparent objects is a limitation of the current pathtracer implementation and it will go away when the new lighting algorithm will be finished - in the full 2.3 beta.

[andi]

Ah, good news. I wasn't to stupid and Octane will get "real" transparency soon, perfect!

Thanks a lot Matej!

[andi]

I will buy Octane now!

[matej]

I will buy Octane now!

There's a workaround we currently use to avoid this light passing limitation, sew this post by Roubal. This applys when you need your emitter to shine through transparent objects, for shadows from opacity-mapped objects you'll have to make up your own solutions how to avoid showing incorrect shadows on your render...

[cornel]

I hope you don´t mind if I hijack this thread, since I think we share the same issue:

I haven´t seen any good & crispy caustics rendered by octane in the gallery, so I tried to do a quick and dirty test on my own. Hmmm... with strange results.

I guess that`s also the glas-bug you were talking about.
Feels like octane distributes thousands of fireflies to get the basic shape of a caustic pattern.

With pathtracing enabled, a GTX460 needed 27 mins for this, with no big detail enhancement since 10 mins, although it´s normally a blazing fast card.

Will this be fixed by the new light-algorithms?

cheers,
:c.

[matej]

@cornel,

I remember Radiance saying that the new algorithm will be more efficient at rendering caustics. I guess that means more crisp and bright caustics. This may be connected to the 'glass bug', I'm not sure.

[andi]

@matej:
thx for the tip, but this technic would not work in my case. I would like the real light refraction caused by complex glas bodies.

@ refractive software:
please make octane refractive soon! Refraction is even in your logo!
btw. why does the octane logo only have 6 arms? wouldn't 8 fit better with the name?

@cornel:
you may hijack, but please tell me what caustics means in this context.
best wishes from the Niederrhein!

[radiance]

@matej:
thx for the tip, but this technic would not work in my case. I would like the real light refraction caused by complex glas bodies.

@ refractive software:
please make octane refractive soon! Refraction is even in your logo!
btw. why does the octane logo only have 6 arms? wouldn't 8 fit better with the name?

@cornel:
you may hijack, but please tell me what caustics means in this context.
best wishes from the Niederrhein!

Hi,

Octane currently does caustics fine, but not very efficient, as such some caustics can take a while to converge, which is being worked on with the new rendering algorithm in development.
The demo is also rather old (2.2, we're currently at 2.3 for licensed customers, which does caustics better through importance sampling)

Radiance

[andi]

@ cornel: as crispy as it gets, or at least i could get it with a small blackbody mesh lamp (with 64000 samples/px), see the second picture.

@ radians:
sorry, i really thought octane could not handle specular materials right, but it works just fine with texture environments or mesh lamps (second picture). i was just mislead by the result you get, using a daylight environment. I still think it can't be physically correct. I can't hardly see any difference between the shadow of the opaque rectangle and the shadow of the glass rectangle in the first picture.
Thank you for the answer!