SDS Caustics in a nutshell

Use this forum for general user support and related questions.
Post Reply
igmar75
Donor
Posts: 6
Joined: Tue Jun 16, 2020 7:43 am

SDS Caustics in a nutshell

Post by igmar75 » Mon Jul 27, 2020 2:34 pm

Hi,
first of all, thank you for Luxrender. It is invaluable.

I'm experimenting with specular-diffuse-specular caustics with Path Tracing and PhotonGI Caustic Cache. After some search and tests (maybe not enough..) I'm still confused about the minimal configuration required to see caustics through mirrors; attached, a not-working example. Is there someone able to give a very basic list of to-do in order to have the SDS caustics working with PhotonGI Caustic Cache?

Thank you!
Igmar

Blender v2.83.3
LuxCore 2.4
Win 10 64bit
Attachments
Caustics_through_mirror.blend
(1005.53 KiB) Downloaded 8 times

User avatar
Sharlybg
Donor
Posts: 2155
Joined: Mon Dec 04, 2017 10:11 pm
Location: Ivory Coast

Re: SDS Caustics in a nutshell

Post by Sharlybg » Mon Jul 27, 2020 2:53 pm

You have to make your twos cube renderable in the collection.
sds.jpg
blend
Caustics_through_mirror.blend
(1006.9 KiB) Downloaded 10 times
Support LuxCoreRender project with salts and bounties

Portfolio : https://www.behance.net/DRAVIA

igmar75
Donor
Posts: 6
Joined: Tue Jun 16, 2020 7:43 am

Re: SDS Caustics in a nutshell

Post by igmar75 » Mon Jul 27, 2020 3:21 pm

The caustic cannot be seen in the 3D Viewport?

User avatar
Sharlybg
Donor
Posts: 2155
Joined: Mon Dec 04, 2017 10:11 pm
Location: Ivory Coast

Re: SDS Caustics in a nutshell

Post by Sharlybg » Mon Jul 27, 2020 3:51 pm

igmar75 wrote:
Mon Jul 27, 2020 3:21 pm
The caustic cannot be seen in the 3D Viewport?
SDS caustic is generated by caustic cache.It is a cached solution. only light traced caustic can be seen in the viewport because they are not cached but directly computed.
Support LuxCoreRender project with salts and bounties

Portfolio : https://www.behance.net/DRAVIA

User avatar
B.Y.O.B.
Developer
Posts: 3681
Joined: Mon Dec 04, 2017 10:08 pm
Location: Germany
Contact:

Re: SDS Caustics in a nutshell

Post by B.Y.O.B. » Mon Jul 27, 2020 4:06 pm

All caches currently in LuxCore are only computed for final renders.
It does not really make sense to compute them in the viewport because they would need to be re-computed on every geometry or material change, and cache computation is usually too expensive for real-time feedback.

igmar75
Donor
Posts: 6
Joined: Tue Jun 16, 2020 7:43 am

Re: SDS Caustics in a nutshell

Post by igmar75 » Mon Jul 27, 2020 4:07 pm

Thank you!
Igmar

igmar75
Donor
Posts: 6
Joined: Tue Jun 16, 2020 7:43 am

Re: SDS Caustics in a nutshell

Post by igmar75 » Tue Jul 28, 2020 9:00 am

1) I continued experimenting, and I found a possible cause of confusion: even if I leave checked the "Caustic Light Cache" file (under "Persistence"), it is not updated! To update it, I have to change the cache file name; unflagging and flagging again the checkbox will not work. Attached you can find the test file. I think you should try to reproduce this behaviour on your machine..

2) Moreover, I noticed that I have to put the Roughness (of the big cylinder) to a value >0.25 to have it collecting caustics. This is not in agreement with the Glossiness Thresholds, whose value is 0.05.

Any idea?
Attachments
temp.blend
(1.07 MiB) Downloaded 7 times

Post Reply