A7 - my first renders - artifacts

[jhindley]

Hi Guys,

First post from me having now used A7 albeit with the demo scene.

I have posted my results here for comment.

I have rendered out the test scene with A7 on Max 2015
I am using a i7 with 8GB Ram

The render was set to stop at 500 passes and I am pretty damned happy with the 1080 render
given it looks pretty clean to me after 2 hours 6 mins.

My question relates to the artifacts in the door frame on the left side of the image.
Is this likely to be something that gets better with more passes or is there something I can tweak to get rid of this.

As I say i think the rest looks clean enough - I would just like to get rid of this artifacting

Any help / advice welcome

[Ludvik Koutny]

That's not an artifact, just noise. It's the slowest converging portion of the image. It's due to the direct environment light having difficult path to reach that area. You can increase light samples multiplier to let's say 4, and let it cook a little bit more. The scene is fairly fast, so letting it go for say 200 more passes should not hurt.

Alternatively, you can just region render that small part with noise, and it should go very quickly away.

[jhindley]

Thanks for the quick reply

Where can I learn how to region render a portion and have it add that to the over all image.
I believe this is possible ???


I mean can i render the $h17 out of that area and then keep that part and continue to render the rest of the image ?
If so where do I learn how or can anyone tell me how quickly ?

[Paul Jones]

James,

At the moment you have to do the comping in post production, but I believe it is part of the roadmap for corona

[Ludvik Koutny]

It is actually ultra-easy:

I've made a quick video to show you how:
https://www.youtube.com/watch?v=1FzWevplrI0

There's only one important thing to keep in mind. Due to the bug in VFB, when you render region, and then click save, it will only save the region, EVEN if there is some remaining data from previous render outside of the region. It will always save just region with black around it. But luckily, you can work around it by clicking Ctrl+C button and pasting it in Photoshop, or even MS Paint ;)

[jhindley]

Thanks guys,

Good evening Mr Jones - good to see you

Rawalance - thanks for the vid

Ill give it a whirl. The machine is currently balls deep rendering out that scene again but this time I upped the setting to 4 as you suggested.
I also gave it another 200 passes so we shall see what the result is like.

I think in production if i was pushed I would region render and comp as you suggested -
I am just getting a feel for the renderer as this is literally the first thing I have hit F9 on it ages

I will post my result with the amended settings and we shall see.

Thanks again for your advice

[jhindley]

OK - so light samples multipler jacked up to 4

I gave it 700 passes this time - this is full screen render not region and not comp'd

Have a look - im still not happy with that area

any ideas

[jhindley]

Ok

Using region render and compositing the layers in PS i have done some tests

I have jacked up the light samples multiplier first from 2 to 4, then from 4 - 6 and finally to 10

I have then rendered out 1000 passes of the region before putting it together in PS

I am still not happy with how this is looking. Any further suggestions ?

[Ondra]

try decreasing max sample intensity

[Ludvik Koutny]

I don't see any noise. If you do, and are not happy, then make yourself your own scene :)

[lacilaci]

Alright.. so.. there is a "problem" in that scene.. There is an opening that lets sun go through without a portal and it is exactly lighing that specific area... solution, place a plane covering that opening and assign portal material to it..

[Ludvik Koutny]

Yes, if you look at the sofa, there is a hole between the back seat cushion and the shelf, and blue light from sky comes through that hole. Only artifact there is noise. If there is no noise, then that's how it would look in the real world.

[lacilaci]

Do this (picture).. or close off that area completely if you want.

[jhindley]

I don't see any noise. If you do, and are not happy, then make yourself your own scene :)

I note the smiley so I know you don't mean that in a nasty way -

I don't know nearly enough about Corona right now to even pass judgement on anyone's scene
I am at the empty room with a tea pot and sun system in it sort of stage right now. :)

I thought your demo scene was excellent and I have enjoyed looking at the settings - the materials and playing with the renderer

It has helped me get a good understanding of the renderer in a very short space of time.

I can see the effect the portal has on the image and I now understand its about the way the direct light penetrates the scene.
I have learned from this and I can now make my own scene to start using as my own test bed.

I hope I can post that scene up when finished for other people to test with.

Lets see where I get to.

Thanks again for your help -

[jhindley]

It is actually ultra-easy:

I've made a quick video to show you how:
https://www.youtube.com/watch?v=1FzWevplrI0

There's only one important thing to keep in mind. Due to the bug in VFB, when you render region, and then click save, it will only save the region, EVEN if there is some remaining data from previous render outside of the region. It will always save just region with black around it. But luckily, you can work around it by clicking Ctrl+C button and pasting it in Photoshop, or even MS Paint ;)

Interesting Rawalanche - I followed your tutorial video on region rendering

when i regioned out that area behind the book shelf and then hit control c and paste into photoshop the entire render came with it - not just the small area
I did not get the black box issue -

My test image in photo shop is now a series of renders layered over my original "noisy" render but each is the full scene render

Has this been addressed in A7 or something because I dont get he same issue you mentioned

The ability to region out a trick part of a shot and then continue with that part done and build the rest of the image around it will be cool.