Soft Shadows

[Peter Milner]

The Hybrid engine is really struggling to smooth out soft shadows.

Here are two test renders. The lower Path Tracer image was run for 2000 passes and the upper Hybrid was run for 4000.

It seems that no matter how long I run the Hybrid render for, it never gets any smoother.

[Peter Milner]

Here's a small section of a hi-res render run for 6000 passes with the Hybrid engine. Notice the grainy soft shadows either side of the plant.

[Roy Hirshkowitz]

Interesting.  Doing some more "engine work" is on the schedule for a few months out.  It would be nice to have some models to work with if you're willing.  No rush, obviously-- we can get to it later.

[Roy Hirshkowitz]

Definitely found a problem here-- do you have a test model I could use to verify?

[Peter Milner]

I've just uploaded a model to you.

[Roy Hirshkowitz]

Here's the thing (in nXtStudio) after about 700 passes (1/2 hour).  Does this look better?

[mike makki]

what is the sun intensity ?

[Peter Milner]

Difficult to tell as the whole image is quite small and grainy.

If you make the floor a flat white colour it may show up better.

[Roy Hirshkowitz]

Here's yours in higher res after 1500 passes...

[Roy Hirshkowitz]

Here's one of mine-- after 20 minutes or so.

[Peter Milner]

After 1500 passes, that's still looking very grainy.

I'm just doing a small experiment to see if the IOR of the glass windows makes any difference.

I'll post the results shortly.

[Roy Hirshkowitz]

It does seem to be resolving really nicely, in both of these models.  Like, I said, there was a problem here which was likely adding some unresolvable noise.  There will still be some differences remaining in the engines-- don't forget that the hybrid passes are up to four times faster than the pt ones.

[Peter Milner]

The IOR of the glass windows does seem to make a difference when using the hybrid engine.

The attached images have 4000 passes with the hybrid and 2000 passes with the path tracer.