Render issues

[Wallace Amorim Júnior]

Here's the issue: renderizei an interior scene, and saved in 3 images in different times.
I used the hybrid.

This first image took 35 hours for 1534 steps.

 

The second  one (bellow) took 38hs30 to 1688 passes.

And the last one, 44hs06 to 1931 passes.

But there are no real differences between them. The nxt peaked in 1500 passes did not solve the areas with poor lighting and reflective materials.
What to do?

I've seen rendered images done in fewer steps with optimal results.

[Wallace Amorim Júnior]

Me and my poor "Portuglish".

[Roy Hirshkowitz]

The last little bit may take a long time to resolve and may not be practical.  There probably isn't anything you can do-- the lighting in this scene is likely quite difficult to resolve.  Photoshop.  You can, BTW, if you save these things as .nXtImage files, combine all three runs in the Image Editor.  That would give you the equivalent of about 5000 passes for this image-- it's possible that would help.  

I think they all look really nice, particularly if you're willing to step the resolution down in Photoshop.

[Wallace Amorim Júnior]

Do you mean combine these three runs that I did? Because i don't think that combine 3 virtually identical images (all of then make on hybrid) will do make any difference. Or are you talking about make one render for each engine and then combine those?

I'm not really a PS expert, and what I did there, only enhanced the granular effect of the materials, especially the leather of the easy chair.

I start up a run using the standard engine. The test with path trace shows almost the same results of the hybrid.

[Roy Hirshkowitz]

Yes, you can combine runs with the hybrid engine in the Image Editor.  For example, combining 3 runs of 100 passes will yield the equivalent of a 300 pass rendering.

[Wallace Amorim Júnior]

How this process works? I was doing on "Image>Arithmetic>Combine Path Tracings", and nothing happens. The command is only available if I open an image first. Then I chose another image to blend via"Image>Ari..." , but the image maintains the same aspect.

Anyway, I've open one of the image (the third one i showed up in the page), and start to play with channels and saturationa amount. And this is the result:

Still, I wonder how, exactly, to combine two images.

[Roy Hirshkowitz]

You've got the idea.  You open one image, then use Image->Arithmetic->Combine Path Tracings and select all of the others.  Try it first this way:

• Run a hybrid tracing for just a few passes (10 for example.)
• Save the result to an nXtImage format.
• Do the same thing again-- just start it over-- and save the result.
• Combine the two using the Image Editor.

In this case the effect should be obvious.  When you're combining images which have resolved substantially the effect will be less obvious (i.e. there might be a huge difference between 10 and 20 passes, but there might not be very much difference between 1000 and 2000.)

[Wallace Amorim Júnior]

But, if I run a hybrid for 1500 passes in 30hs, and then do the same thing-starting it over for more 30hs-I'll have two images after 60hs, to have a 3000 passes efect. If i let the nxt run for 60hs straight, will I not have the same effect of 3000 passes?

BTW, can I merge diferents kinds of engines (standard and hybrid, for exemple)?