Caustic glas test in Beta version 3.1 alpha.
pls give blend file i want test it in other render engines
ok I will do it
Any news or changes regarding caustics in 3.1 beta? There is nothing about it in the changelog:
https://wiki.blender.org/wiki/Reference/Release_Notes/3.1/Cycles
@Video_TT , I think you have some things not set up correctly in your test file. The rendering you posted is the same result youâd get from the daily 3.1 build.
You have âCaustic Lightâ turned off (world->Settings->Surface), and you have Caustic Caster and Receiver both on for everything.
I turned Caustic light on, then I turned Caustic Receiver off for the glass materals (leaving them with Caustic Caster). Then I turned off Caustic Caster for the ground, so itâs just a Receiver. Strangely, if I left Caster on for the ground, the whole rendering looked like Caustic Light was turned off. Bug I guess?
Here are the results with those things corrected:
Hereâs a LuxCore render with the lamp correctly adjusted (as close as I could get)
CPU/GPU Path + Light Tracing
CPU Bidirectional Path Tracing
Yep - the way caustics work in the experimental 3.1 build are as follows:
- Your light must have âcaustic lightâ enabled (I believe this also works scenes lit with HDRI - but there is a separate toggle on the world panel to enable that - under sampling)
- Any glass objects you want to enable caustics for must be set to âcaustic casterâ
- Your ground plane or any objects that the caustics may fall on must be set to âcaustic receiverâ
Some additional important points:
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In the render panel, under light paths - your âfilter glossyâ value must not be zero. I have found values of 0.01 and above work just fine (I believe the default is 1, so you shouldnât need to touch this - the actual value appears to make no difference for these types of caustics).
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You must also have refractive caustics turned on in this panel. This should be on by default if you have selected the âfull global illuminationâ preset.
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Setting an object to be both a caustic caster and receiver at the same time can cause some weird behaviour. I have found that glass objects can become much darker, although it doesnât seem consistent (we have to remember this function is at an early stage of development). Iâd avoid doing this for now.
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This technique doesnât currently work for reflective caustics.
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Be careful if you scale your objects. If you inadvertently invert the scale , it can screw up the caustics even though the object face normal appear to be facing the correct way. If you are unsure - apply all transforms to your object - then check the external face normals are blue.
There is also a thread running here for more examples of this in use - including some testing around the scaling issue in point 5 above.