LF Iray Help - Light Emitter & Caustic Effects - Pyramid & plane

linvanchene

I am trying to get a better understanding of Iray and currently hit a road block with light emitter settings to achive caustics.

Test Scene:

Ground plane 100m

Pyramid - Cone with 4 sides

light emitter plane 10cm = 0.1m

The small plane is supposed to emit light rays that are redirected when entering the glass pyramid. (Refraction)

They travel through the pyramid glass volume and leave it again on the opposite side leaving a caustic pattern on the ground plane.

Side Note:

The index of refraction determines in which angle the direction of the light rays are altered when entering the glass pyramid.

The dispersion coefficient determines the coloration of the caustic pattern created on the ground floor.

compare:

https://en.wikipedia.org/wiki/Refractive_index

https://en.wikipedia.org/wiki/Refraction

https://en.wikipedia.org/wiki/Dispersion_(optics)

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To start a screenshot of what I am trying to recreate in Iray.

 

 

In the standalone version of OctaneRender I set up the following scene:

 

The Glass material of the pyramid has the following values

Index of Refraction 1.488

Dispersion coefficient 0.030

The values are a bit random but they create an interesting caustic effect.

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One challenge might be to set up similar Index of Refraction and Dispersion Coefficient values.

But I am stuck at a completly different point: Light Emitter Settings in IRAY

The first try was a very small 10x10cm light emitter plane.

 

 

With the default light settings there is almost no light hitting the scene at all.

I made sure the normals of the light emitter are pointing in the right direction.

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I tried then a larger plane as light emitter with 1x1m

I used the light emitter preset from default lights and shaders.

Tried to upload screenshot without success.

Still the light is not strong enough and is barely hitting the pyramid.

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I then moved the luminance value up to an insanely high value of 1'558'000

 Tried to upload screenshot without success.

And still the light does not seem to travel a longer distance.

But now you can observe the highlights of the area close to the emitter to get incredbily bright and starting to blow out towards a maximum white light.

Loosely put: 

Why is the light just getting brighter but not traveling further? Am I missing some settings somewhere that change this behavior?

 

The questions:

1) What do I have to change in the settings of the light emitter for the light rays to travel further trough the glass volume to leave a caustic pattern on the floor behind the pyramid?

 

2) Are there any other settings I should adjust in other tabs that affect the strenght or more precise the reach of light emitters?

 

3) Which settings do I need to adjust to get the highest quality caustic effects in Iray for DAZ Studio?

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The scene file "Pyramid Plane Emitter v1003.duf" is attached to this post in .zip format.

 

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Side Note:

Why does the upload of two addtional screenshots keep failing?

It just displays uploading but nothing is happening.

I tried to make the images even smaller (37kb) in photoshop and still no progress.