caustics through architectural glass

[peterguthrie]

Hi chaps,

Is it possible to exclude objects from the caustics calculation?

I want my nice caustics from a pool to go through some glazing and appear inside the building, but I dont seem to be able to do that in one pass.

any ideas?

Peter

[peterguthrie]

I suppose the standard technique would be to hide the glass, calc the caustics, save it and unhide the glass?

[Dariusz Makowski (Dadal)]

Right click > Vray Proporties> Caustic tick boxes? That dont do the trick?

[peterguthrie]

nope - they dont let the caustics pass through

[peterguthrie]

how do saved photon maps for caustics work? what do they contain? is the saved solution view dependent?

Vlado?

(lots of questions, sorry!)

[trixian]

Photon maps should be world-space afaik

[vlado]

The caustics photon map is completely view-independent.

If the caustics doesn't make through the layers of glass, it may be that the refraction depth in your materials is too low.

Best regards,
Vlado

[peterguthrie]

thanks Vlado, how about if the glass material has affect shadows ticked?

[Zdravko.Keremidchiev]

If you enable Affect shadows, the glass material won't generate caustics. Make sure the option stays off if you need the caustics effect.
Affect shadows option simulates shadows when there are no caustics in the scene. There is no point using this two options at the same time.

[Mokiki]

I think Peter means "affect shadows" off for the glass where the caustics should just pass through. But maybe I'm wrong.

[peterguthrie]

I mean affect shadows in the glass material. For architectural glass, relying on caustics to see through the glass is not a practical solution.

[peterguthrie]

here is a sketch - for this to work I need to hide the glass, calculate the caustics, then unhide the glass and render with saved caustics solution.



so to my original question - can I hide the glass object from the caustics calculation?

[Mokiki]

I just rebuild your sketch quickly and see what you mean. But I managed to let the caustics pass through with "visible to GI" ticked off inside the vray properties on the glass window. Only odd behavior is that the glass is pretty dark even with "affect shadows ON".

Uploaded two render: the only difference between the two renders is that caustics inside the GI settings is activated on the first render and deactivated on the second.

[vlado]

Oliver, can you post your scene?

Best regards,
Vlado

[Mokiki]

Sure vlado@chaosgroup.com was the correct email?

*edit* Sent. Forgot to mention the max version is 2015.