Unwanted Ambient Occlusion-looking effect in Corona

Corona Corona for 3ds Max Help Required
1

Hello,

I am experimenting with Corona - trying to incorporate it into my main workflow as it is excellent at first glance. Most ‘issues’ I have had are solved by a little bit of research on my part, but I cannot figure this one out. My image exhibits small shadow lines around certain objects and details around the ceiling (see attached) - an effect very similar to the Ambient Occlusion option in Vray that can be embedded into the render - only I cannot find any option to control this in Corona. I’ve tried various plain materials to the same effect.

The image is 1500x1500px and around 900 passes - the areas highlighted in red on the attachment are the problem areas.

Any help would be so greatly appreciated!

2

Do you have rounded corners enabled on that material? If so, try to disable it or reduce radius.

3

Thanks - but no, rounded corners are not turned on. I tried turning them on just to see and the effect is the same off or on.

D

4

Looks like AO indeed. Can you show material setup for the wall and ceiling parts?

5

Of course - the material set up is attached. The wall and ceiling have the same stucco material, with a simple UVW map.

MATERIAL SET UP.jpg
MATERIAL SET UP.jpg3300×1776 852 KB

6

You have displacement enabled and its max level is set to 100cm. What is your scene scale?
Also, can you show how that stucco_normal texture looks?

7

Is the same material applied to wall and ceiling parts? I would bet either on displacement as Romullus suggested, or reflectivity. Can you disable both and see what happens?

8

Thanks chaps, but no joy.

My scene scale is in cm. I did the following:

  • disabled displacement and adjusted the levels
  • disabled reflectivity
  • disabled all the maps for the material so that it is just a flat colour

It is the same material for ceiling and wall. I tried a different HDRI source, different rotation - same issue.

A crop of the normal map is attached, but I disabled it anyway to no avail.

  • D.

NORMAL _ TROUBLESHOOTING.JPG
NORMAL _ TROUBLESHOOTING.JPG864×823 231 KB

9

I’m asking about size of your scene not a units. For example is your table 100cm or 10000cm tall? You should always work as close to real world scale as you can.

Normals maps should be used like this: https://coronarenderer.freshdesk.com/support/solutions/articles/5000501663-how-to-use-normal-maps-

Create new material and assign it to global override. If it still renders wrong than maybe there’s something wrong with geometry?

You can upload scene here and someone will pick it up and will take a look.

10

Yup, that would be great, or at least some isolated parts of it where the problem is visible. Or to out helpdesk if you prefer: https://coronarenderer.freshdesk.com/support/tickets/new

11

Ok, so I solved it. Or rather I discovered and deleted a vray light and some vray materials hidden in the scene a long way from the camera, but it seems they were understandably messing with Corona’s calculations.

But thank you very much for the help - I really do appreciate it!

Speak soon.

D