Solution: Refraction Material Effector not working in Final Render

[robcat2075]

In the "Heat Distortion" Thread I posted a sample project that uses a Material effector to change the refraction value of a small portion of a lumpy transparent tube.

 

HeatDistortion.zip

 

The idea is that where the refraction is greater than 1.0 the lumps will bend the light and distort the background seen through the object, creating something like the wavy distortion you seen in the air above a very hot object.

 

You may also recall a similar tactic used by Jeff Lew in "Killer Bean 2" to make the "trail" of a bullet in the air visible.

 

However the effect only appears properly in Progressive render, not Final renders. Steffen Gross has looked at the problem and found that it will be difficult to fix (many potential side effects) but also found a simple work around:

 

Set the "Density" of the lumpy object to some small value like 0.0001 (anything smaller than 0.01 will display as 0). That will force the refraction of the lumpy object to render where the Material Effector intends it to render. ("Density" is like Transparency but varies the transparency based on the thickness of the object. A tiny Density value will have no visible effect in most cases.)

 

heat.mov

 

I post this for posterity in case anyone in the future is stumped by this small render bug that may not be immediately fixed.

[Kamikaze]

Robcat

 

Thanks for noting this........and the project file

 

Mike C

[johnl3d]

Nice tip !