Strange material behaviour

[mrjojo]

Hi,
Im getting really weird (reflections?) along the edges of my objects. If you look closely at the coffee mug or the eggs youd see what I mean.Any ideas what might be going wrong?

[maru]

Unfortunately it looks like this, so this would be expected:
https://forum.corona-renderer.com/index.php/topic,4542.45.html

Solution is to change material settings, for example reduce reflectivity.

[GestaltDesign]

Could another option be to revert back to the old default BRDF by ticking the 7. 2 legacy checkbox in the advanced rollout, you may get more predictable results.
If you are desperate for GGX without significantly changing material behaviour you could try the nested blend approach as described in this thread:
https://forum.corona-renderer.com/index.php?topic=4260.0

[mrjojo]

Unfortunately it looks like this, so this would be expected:
https://forum.corona-renderer.com/index.php/topic,4542.45.html

Solution is to change material settings, for example reduce reflectivity.

You mean reduce reflectivity level, or the reflection color to a darker value?

[maru]

Unfortunately it looks like this, so this would be expected:
https://forum.corona-renderer.com/index.php/topic,4542.45.html

Solution is to change material settings, for example reduce reflectivity.

You mean reduce reflectivity level, or the reflection color to a darker value?

It should have the same result.

[mrjojo]

I set the reflection level to 0.8 and heres the result after 95 passes which took bout 27 minutes. I also put my render setting next to my render.Tell me if these settings are any good for a clean and noiseless render? if not what would you suggest?

[maru]

Is this 1.0 version? Use UHD cache indstead of HD.
Is your problem too much noise or that it takes too much time? I can't see much noise in this image.

[mrjojo]

Is this 1.0 version? Use UHD cache indstead of HD.
Is your problem too much noise or that it takes too much time? I can't see much noise in this image.

Yea im using 1.0 demo version. Im new to Corona so I wouldnt know what the best balance between quality and time?

[maru]

Generally, if you have some goal rendering time you would like to achieve, and you get bad results in it (for some reaseon), you can:
-ignore noise for now and see how many passes produce good edges of geometry and textures (or example if it's 16 passes, or 32, or 64?)
-then use the lowest possible number of passes (let's say 16)
-render 16 passes and see if there are any other problems (noise?)
-if there is noise, this most likely means you need to increase sampling settings, either GI/AA value or LSM
This is just an example. If you don't care so much about rendering time, you can simply set no time/pass limit and just wait for the image to refine.

Maybe this guides will be helpful:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000516729
https://coronarenderer.freshdesk.com/support/solutions/articles/5000516731

[romullus]

Something is wrong with your image, there's almost no contact shadow. Check your material settings and or HDRI quality.
Render settings are also wrong. If i'm right, there's no enclosed enviroment in your scene. In that case you don't need such high GI samples. Set GI vs. AA to 8 and LSM to 4.

Your liquids are modeled incorrectly. Look here how to properly do this in Corona: https://coronarenderer.freshdesk.com/support/solutions/articles/5000515618-how-to-model-a-liquid-in-glass-in-corona-

Also you're getting too lowperformance out of your CPU. Might be due to bitmap paging. Read this: https://forum.corona-renderer.com/index.php/topic,1662.msg12232.html#msg12232

[mrjojo]

Something is wrong with your image, there's almost no contact shadow. Check your material settings and or HDRI quality.
Render settings are also wrong. If i'm right, there's no enclosed enviroment in your scene. In that case you don't need such high GI samples. Set GI vs. AA to 8 and LSM to 4.

Your liquids are modeled incorrectly. Look here how to properly do this in Corona: https://coronarenderer.freshdesk.com/support/solutions/articles/5000515618-how-to-model-a-liquid-in-glass-in-corona-

Also you're getting too lowperformance out of your CPU. Might be due to bitmap paging. Read this: https://forum.corona-renderer.com/index.php/topic,1662.msg12232.html#msg12232

Thanks a bunch man very informative. However, what is there to be checked in my materials tho? what might be preventing the contact shadows?

[mrjojo]

Generally, if you have some goal rendering time you would like to achieve, and you get bad results in it (for some reaseon), you can:
-ignore noise for now and see how many passes produce good edges of geometry and textures (or example if it's 16 passes, or 32, or 64?)
-then use the lowest possible number of passes (let's say 16)
-render 16 passes and see if there are any other problems (noise?)
-if there is noise, this most likely means you need to increase sampling settings, either GI/AA value or LSM
This is just an example. If you don't care so much about rendering time, you can simply set no time/pass limit and just wait for the image to refine.

Maybe this guides will be helpful:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000516729
https://coronarenderer.freshdesk.com/support/solutions/articles/5000516731

Thanks for the links. Tho, do you have any idea why im not getting contact shadows out of my materials?

[mrjojo]

Hey guys, heres a quick update, I remodeled the liquid based on the link that romullus provided but the milk renders kind of odd looking as if its outside of the glass.

P.S: I rendered the scene with a different HDRI which is quite high res (200mb in size) but still im not getting any contact shadows! :(

[maru]

but the milk renders kind of odd looking as if its outside of the glass

This is correct. See http://upload.wikimedia.org/wikipedia/commons/9/9d/Presidents_Choice_-The_Decadent,_chocolate_chip_cookie,_with_a_glass_of_milk.jpg Your glass is very thick, that's why it's even more apparent.

Contact shadows - I think it's more dependent on light than on materials unless your are using an incorrectly set up bump map.

[mrjojo]

but the milk renders kind of odd looking as if its outside of the glass

This is correct. See http://upload.wikimedia.org/wikipedia/commons/9/9d/Presidents_Choice_-The_Decadent,_chocolate_chip_cookie,_with_a_glass_of_milk.jpg Your glass is very thick, that's why it's even more apparent.

Contact shadows - I think it's more dependent on light than on materials unless your are using an incorrectly set up bump map.

well as far as light goes, im using an HDRI in the environment slot, thats pretty much it. Is there anything to do to get decent contact shadows without doing it in post?