Author Topic: Direct sampling CoronaLightMaterial  (Read 2437 times)

2015-09-02, 17:03:17

Nik

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Hi, I want to discuss meshlight sampling in Corona.
VRay have samples spinner, Corona doesn't. Cleaner UI, faster setup and so on, I know. But there is one problem with meshlight.

I'm not sure that I'm totally understand Corona sampling algorythm, but it seems that one single mesh have the same priority as one light source (it's called light group). That's nice and right in some situations and maybe in most situations, but when you have single ceiling backlight mesh that goes through big scene, then you have very very undersampled direct light from this meshlight.

Increasing Light Samples Mult is not optimal solution because it oversamples other lights, and I got undersampled gi-glosy as result.
There is one stupid solution for now - detach all polys of this mesh, so each one will be sampled like one light source. Do I need to tell that this is very uncomfortable way to work with meshlights? :) For example, I have Line->Sweep and I can edit this mesh easilly by editing Line. Editing of line that made of detached polys is a big butthurt.

I understand that simple UI and easy workflow is Corona's priority and I love that. But detaching polys to get proper sampling isn't simple and intuitive way. Maybe one more checkbox in CoronaLightMaterial won't ruin UI?

2015-09-02, 17:17:41
Reply #1

maru

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Hi, Ondrej should be able to answer on all of your technical questions, and I only wanted to make sure you are not misusing light mtl and self illumination:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000515603
What kind of scene are you rendering? Can you show screenshots or renders where the problem is visible?
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2015-09-02, 17:27:08
Reply #2

Nik

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Oh, no no, I'm not misusing self illumination. Self illumination doesn't affect DirectLight pass at all, only Indirect.
I talk about noise in Direct light only.

I'll prepare some images for you. This is not scene related problem for sure

2015-09-02, 17:32:53
Reply #3

Ondra

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checkbox to detach polygons would be nice. But even better would be automatic system that optimally detaches long lights into several segments. We are working on it.
Rendering is magic.How to get minidumps for crashed/frozen 3ds Max | Sorry for short replies, brief responses = more time to develop Corona ;)

2015-09-02, 17:37:05
Reply #4

Nik

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Wow :) ok thanks