Portal Material

[pavel]

Hello,

I have a small room lighten by an HDRI image. I have deleted the glass windows and placed 3 planes on windows just the size of the openings, with normals facing inside the room, covered all openings, but it doesn't seem to do anything. I have checked the render speed or quality with and without portals but there is no difference.The room is not brighter, or less noisy either. Am i doing something wrong?

Thank you,
Alex

[bepeg4d]

hi,
the portal material works only in a particular condition, if the camera is inside a closed perfectly box with only a little aperture for entering the light. if the hole is closed with polygon with the normal pointing inside, then the portal material assigned to the hole-polygon can efficently bring the light inside the box. unfortunately in standard interior scenes is difficult to have exactly this condition, so the best way, in my experience, to bring more light in the room is to use a diffuse emitter material with 0 opacity instead of the portal material. in this way you can have a much better control over the indirect light and it help a lot for cleaning faster the noise
ciao beppe

[aoktar]

i suppose, you never checked the 1.50's manual. Please read section of Using Portals.

[pavel]

I actually check the manual all the time aoktar and i have read several times about portal material and done exactly as it's written:

-room completely closed
-camera inside the room
-deleted glass material
-assigned portal material to planes that enclose the hole completely
-normals facing inside the room
-least amount of geometry as possible
-using only path tracing kernels
etc...

I have attached the scene.
Thanks for tip bepeg4d

[pavel]

bepeg4d or aoktar, can you please check my scene and tell me if the setup is right? Thanks

[aoktar]

this is my test render for your scene. just 1-2 min. cooking. It has enough lighting to rid away the noises. Some critism, no need so much bounces for this scene, i did 6-8, also don't do the hotpixel removal is 0, keep between 0.5-1 if you don't have firefly.
And caustic blur is zero makes much fireflys, set to least 0.02 or more.
Also check notes of portal, it says must exactly cover openings. I'm not sure that's working well for all situations.

Hmm, your wood textures has not good colors. I prefer pro textures for good renders

[pavel]

Thank you very much for tips aoktar. It may be 1-2 mins for your system which is much better I always put maximum bounces because i have seen that the render time stays the same, so the more bounces the better, i thought.

If you talk about the desk and table, the textures are photos i have made to the actual furniture, because it is a job for a client that wants the old furniture to stay, so i had to keep it unfortunately The walls and ceiling are from octane DB.

The lighting in your renders look very good and the time is very good also. I used pmc to render and it took about 6 hours and lighting with hdri. I think i am doing something wrong I am going to check the scene again with the changes you suggested.

P.S. I want to buy another gnu, maybe Titan. What do you suggest? I have a gtx780 right now.

Thanks for feedback.

[aoktar]

i use lowest numbers for bounces as possible as. I suppose that's cleaning the output faster. Also caustic blur is important to avoid fireflys. And some times i use some hidden weak lights to help to render engine for decreasing noises.

Btw, 6 hours is like unfinite times for me I never wait more than 30 minutes for a image. Mostly i try to keep under 1-2 minutes, especially for animations. And apply some noise removal if i need.

For your scene, i have changed materials of wood wall and and table's. I never used too saturated and overbrighted textures. Also never give full white. Also, some hdri don't gives good results. You should keep in your mind.

Btw, if you notified that i have two graphic cards(780+590). They has calculation power of two 780ti. I can advice a 780/780Ti or Titan(if money is not a problem). Also 750ti is looking a big potential but it's not yet supporting by Octane.

[pavel]

What method do you use to remove noise? Post in photoshop? Or do you increase the filtersize? I have noticed that you have 2 gpus. I aim for Titan since it has 6gb of ram and i push my 3gb to the limit at the moment.

By the way this is the result after about 6 hours. Both took the same amount of time to render and i just rememberd i have used a sun, not hdri.

Ok, i have done some tests and i reduced the time alot. I get acceptable renders in 5-10 minutes using the tips you gave me aoktar. One question: isn't caustics blur for glass? I don't have glass in that scene, because i deleted the glass windows and placed the plane portals.

Cheers

[bepeg4d]

hi pavel,
i'm glad to see that you are solving your problems
about the caustic blur, not only the specular but also the glossy materials generate caustics, so if you don't need to see them, set the caustic blur to 1 for speed up the cleaning
ciao beppe