U g I n f o r d e s I g n e r s

V-Ray for SketchUp
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Examples
Image on the left is rendered without Caustic effect. Image on the right is rendered with it. The 
values of Max Photons, multiplier, and Caustic Subdivs are all using default setting. With the image 
on the left you can see a slight caustics effect. This is due to the Affect Shadows option. This 
option is actually trying to fake the caustics effect seen on the right.
At the beginning of the render the progress window will say that it is 
calculating caustics. Depending on the number of lights and the 
caustic subdivisions of each light this process may be very quick or take 
a few minutes.
Open file:
, open V-Ray for SketchUp
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s Render Options. Pull down the Caustic 
control panel at the bottom. Check the on to open the Caustic effect.
Chairs-Caustics-01.skp
What are Caustics?
Caustic is a lighting phenomena created by some materials, for example, metal, glass and liquid which either 
reflect or refract light around the object. This happens when the light becomes focused by the materials 
resulting in a pattern of bright light.
Caustics
V-Ray for SketchUp
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If you want to control the quality of Caustic even better, other than increase the intensity of light, 
you can also increase the Subdivs under Sampling from 1000 to 2000 or even higher. But this will 
increase the prepare time for render Caustic effect. 
Image on the right is rendered with Caustic Subdivs set to 3000, you can see the better quality of 
Caustic effect in this case.
Go back to the Caustic
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s control panel. Render it again with the Max Photons changed from 50 to 
300, as the image on the right. Compare with last page you will find the Caustic effect is greater 
this time and smoother.
Usually it
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s easier to spot the Caustic effect in a darker scene. If the scene is brighter, you can try 
increase the Multiplier to offset the difference.