Specular problem (Glass)

[Dionisio]

Hi all, I am very new in Octane and I am doing some simple tests in 3ds Max 2015 to understand better settings how they work. I am personally an Iray user since 2009 but I wanted to give a try at this engine too due to some very cool futures it has.

I have a very weird problem with the specular material. As you can see from the attached image, I use a Daylight illumination and applied a simple specular shader to the box and teapot.I use PMC and the shadows are soooo dark! How this is possible? I remeber a day ago my results weren't like this at all. Don't know if I touched anything by error...

Do you guys have any clues?

Thanks in advance!

Dionisio -

[Dionisio]

Same simple scene with HDRI.

Something is wrong, the engine is very slow and lot of fireflies appear on the objects! Two dasy ago when I tried it the results were faster and cleaner!
Can't figure out these issues...

Thanks,

Dionisio -

[Dom74]

Already encountered this problem, Octane have a very strange behavior with glass, use fake shadow on glass material with alphashadows on, otherwise, noway to resolve light passing through the glass, hope the octane team will work on it.

[Dionisio]

Very very sad to hear this!

Thank you anyway for your answer...

The strange thing is that two days ago the behavior seem different and correct.

Dionisio -

[Goldisart]

only HDRI - fast

[suvakas]

Octane is too slow with caustics.
Play with "caustic blur" value.

There is no competition if you compare iRay caustics speed to Octane.

Suv

[Dionisio]

Guys thank you for getting back! I really can't believe that the Daylight rays can get through the glass material at all!!! This is very disappointing!

BUT, as I already mentioned, when I did my first tests three days ago, seemed everything fine and fast! I can clearly see the problem here.I am working on a scene where before the caustics were very fast to compute and now is damn slow and the sun doesn't gets through the glass anymore... Don't know what is happening.

Thanks,

Dionisio -

[akira]

Guys thank you for getting back! I really can't believe that the Daylight rays can get through the glass material at all!!! This is very disappointing!

BUT, as I already mentioned, when I did my first tests three days ago, seemed everything fine and fast! I can clearly see the problem here.I am working on a scene where before the caustics were very fast to compute and now is damn slow and the sun doesn't gets through the glass anymore... Don't know what is happening.

Thanks,

Dionisio -

Hi, Dom74 has already told you the solution for this problem: use fake shadow on glass material with alphashadows on((from kernel panel of render settings)

[Dionisio]

Yes, thank you again but this is not a physically correct solution. Doing the same simulation with Iray for example, the difference is huge!
Can't imagine complex interior scenes where every glass element produces such results.

Dionisio -

[voltaire585]

Also try changing ray epsilom as this can make a big different if your glass is touching or very close to the surface. That maybe why you had different results at different times, if you changed that setting