Interior render problems

[Alexander Petrov]

Hi guys, i'm triyng to render interior scene. The problem is that, there are many artefacts in scene. Also the carpet texture is beige(lightt), but after render it seems too darkq why?



Carpet texture, i'm using grass bump texture for displaycement.



Render settings

[Micha_cg]

Re: Interior render problems

My hints:

* DMC sampler -> stick at adaptive amount 0.85 allways, value 1 can cause artefacts

* I use LC option "pre-filter" and sample size 0.005 could be small enough

* Irradiance map: your interpolation samples 128 cause a high detail lost and slow speed. For interiors I use 80 .. 200 subdivs (try to keep it low as possible for speed) and (interpolation) samples 20..30. For more speed try max rate -1 instead 0. Color threshold 0.2 could be set at 0.3 for standard use.

* I would try to render the scene without detail enhancement. I have the feeling, DE slow down the calculation of the displacement. Allways I try to get so much as possible per IM only, because it's a fast method. I use DE only for very special cases only - small details like gaps everywhere, but for this interior ...

* noisethreshold 0.005 is very strong - I use 0.015 most or 0.01

[dalomar_cg]

Re: Interior render problems

The carpet is most likely darker just because of self shadowing. Also DMC tends to yield darker results when undersampled, which is likely what's happening with the way you have DE setup here. I agree with Micha that DE probably isn't the best for this situation.

Other than the few small artifacts, and maybe a too much displacement for my taste, this is definitely a really fantastic image

[Alexander Petrov]

Re: Interior render problems

Hi again gyus, thanks for the quick replyes. Micha i'll corect my settings thank you very much. Thanks for the praise Dalomar So i find where's the problem, and it's called Curtain. I've made some tests witouth curtain and the rezults are :




So i'm wondwring what i'll do. The curtains are made with Vray 2Sided Skip Material, without any textures, only diffuse color, and some transparency. Wken i removed the curtains, render time decreases twice. Also artefacts was disappeared, and the carpet is light. Wkat i'll do? How to create curtain without these problems?

[Micha_cg]

Re: Interior render problems

For the curtain it good be good to set the material "invisible for GI" - maybe it's possible per future releases.

Maybe a simple single side material (transport light from outside to inside) with additional emitter layer (transparency 250 and intensity like it looks good) could be used as fake.
An other attempt could be to add an invisible light parallel to the curtain inside the room. So, you could get a direct light source within the room and the light trough the curtain isn't important for the calculation anymore.

[Alexander Petrov]

Re: Interior render problems

Micha what's mean this - Bitmap "(null)" returned an invalid color (rgb -11404544.000000 -11404544.000000 -11404544.000000). The render delayed there, is that a bad texture or bump?
Also, what is "ordinary" quantity of LC Subdivs for interiors 1000 or more?

[Micha_cg]

Re: Interior render problems

Also, what is "ordinary" quantity of LC Subdivs for interiors 1000 or more?

I use so much subdivs so that the image looks well sampled, not so much dark pixels are visible at the LC pass anymore. But the LC pass is quite robust. My tests show me in the past, that very low subdiv counts cause not a visible bad quality most. If the LC pass is quite fast, than I would try to use 1500 subdivs or more (if the LC pass isn't nice looking). The needed subdiv count is dependent from the sample size: bigger size, less samples, less GI details sometimes.

The other problem - it's discussed in the past, but if I remember me, without a solution. It's an error message and I have the feeling, it can cause crashs. I have seen wrong pixels at the final image once.

[Alexander Petrov]

Re: Interior render problems

?i Micha, thanx for support I found the reason for the message. It proves that the reason is fake bump. I made a bump for the sofa with Photoshop, and thats the reason for crashes.
Other than, i follow your advices for the curtain and it work perfect, soon i'll post picks
Thanks again :P

[dalomar_cg]

Re: Interior render problems

As for a good light cache subdivision number you might want to check my response @ the link below...you to Micha

http://asgvis.com/index.php?option=c...28253#msg28253