Trace sets

[Neilg]

Just wanted to say how much I love this feature!

Remembered them last week and have been able to set up in a single pass what originally took 5 separate & fairly slow renders to achieve in fusion. Just popped in to take a look and make sure they were working and the end result is flawless.
I think I've just cut my total render time down to 1/4 of what it was originally. They have saved so much time dealing with logistics and organizing all the files needed to do it in passes too.

Top marks vlado & team! they're an incredibly powerful addition for super fine control of how things look.

[joconnell]

Are you using it to fake what sees what in artistic ways or to limit calculations for speed reasons? Interior or exterior stuff and whats your strategy / thought process behind it?

[Sbrusse]

Not sure what you're talking about, can you explain a bit more what you refer to? Seems I'd like that feature too

[vlado]

Just wanted to say how much I love this feature!

Thank you for the kind words I'm glad that it's a useful feature.

Best regards,
Vlado

[joconnell]

Not sure what you're talking about, can you explain a bit more what you refer to? Seems I'd like that feature too

You can choose on a per object basis what can reflect / refract what!

[Alex_M]

Yep, these trace sets saved my @ss on a couple of occasions too. Awesome stuff. For anyone interested there's a great script that allows you to edit the trace sets of multiple objects at once.

[squintnic]

news to me!
will try it out tomorrow
neil what kind of scene is it and what things did you exclude to get such a speed increase?

[Sbrusse]

Nice, great to know that feature, would not need it at the moment but good to know it exists!

Cheers

[Neilg]

Are you using it to fake what sees what in artistic ways or to limit calculations for speed reasons?

Started off as faking what sees what for artistic reasons, but then i started looking into how it could help optimize.
A first version of this scene had an extra pass being rendered of the glass reflecting just the skydome so it could be boosted in post - but it's a complex scene and that pass took 12 hours to render for all cameras. Now the glass ignores the skydome everything else sees and reflects a second one, behind the first - which is 3x brighter and makes the render look the same as i'd set the postwork up to look. There's a few other things like that too, I went through my fusion file looking at awkward bits of extra passes and was able to convert a lot to a trace set single pass. All said and done without any of these extra passes, the total render time & management time for the whole project has come right down.

There is one feature I am still missing on this which I would love vray to have, and have requested before - and thats to set a material/object to not affect the reflection/refraction depth count.
This scene renders in no time at all with a reflection depth of everything set to 1 and looks fine without glass - but in some areas there are 7 layers of glass in front of objects. So now everything has to be on 8+, so going to the camera outside near the vegetation it renders significantly slower than it really needs to as now i've got a jungle with all leaves set to a depth of 8+.
Being able to keep ref depths low across the board with an exception so glass doesn't ruin it all would slash all of my render times quite significantly. adding any amount of glass makes bothering to set proper reflection depths kind of worthless.

[joconnell]

Thanks for the examples, they'll come in useful!

[Sbrusse]

Started off as faking what sees what for artistic reasons, but then i started looking into how it could help optimize.
A first version of this scene had an extra pass being rendered of the glass reflecting just the skydome so it could be boosted in post - but it's a complex scene and that pass took 12 hours to render for all cameras. Now the glass ignores the skydome everything else sees and reflects a second one, behind the first - which is 3x brighter and makes the render look the same as i'd set the postwork up to look. There's a few other things like that too, I went through my fusion file looking at awkward bits of extra passes and was able to convert a lot to a trace set single pass. All said and done without any of these extra passes, the total render time & management time for the whole project has come right down.

Our pipeline It's been years that we need to have a different reflection than what is used for our lighting spec, so we are used to have two dome, one with a HDRI that affects only diffuse and spec and one that only affect reflection and loads a HDRI that is way brighter and orientated to match the perfect reflection we need.
This by passes the need of using - what seems to be a great feature - the trace sets.

There is one feature I am still missing on this which I would love vray to have, and have requested before - and thats to set a material/object to not affect the reflection/refraction depth count.
This scene renders in no time at all with a reflection depth of everything set to 1 and looks fine without glass - but in some areas there are 7 layers of glass in front of objects. So now everything has to be on 8+, so going to the camera outside near the vegetation it renders significantly slower than it really needs to as now i've got a jungle with all leaves set to a depth of 8+.
Being able to keep ref depths low across the board with an exception so glass doesn't ruin it all would slash all of my render times quite significantly. adding any amount of glass makes bothering to set proper reflection depths kind of worthless.

This is a common issue for us as well and we requested something similar that was never picked up :
We would like to have a max depth that would work PAST the refractions only.
Basically :
* the rays that are shot from the obj, when they hit a object with no refraction then they uses the max depth and stops.
* the rays that are shot from the obj, when they hit a obj with refraction, passes through that refraction without counting the depths, and once it passed the refraction, starts to count the depth, till he hits a obj without refraction and stops.

This means we can set the max depth to 1 for all our materials but it will dynamically "add depths" to only the rays that passes the refractions.
It would literally be a live saver as for the moment, once we set our max depths to more than 1 to passes through the glass as you described, our vegetations and other tricky mtls/objs make the render grinds to a halt.
We need to make multiple render passes to fix this and it's a big issue for us in our pipeline, where as, having that dynamic max depth only for refraction would have save our asses more than once and make us meat deadlines way more easily.

I hope this make sense

Stan

[zoranm]

This scene renders in no time at all with a reflection depth of everything set to 1 and looks fine without glass - but in some areas there are 7 layers of glass in front of objects. So now everything has to be on 8+, so going to the camera outside near the vegetation it renders significantly slower than it really needs to as now i've got a jungle with all leaves set to a depth of 8+. Being able to keep ref depths low across the board with an exception so glass doesn't ruin it all would slash all of my render times quite significantly. adding any amount of glass makes bothering to set proper reflection depths kind of worthless.

Just curious. Why don't you just restrict the max depth via the material? What I'd do in your example: set the glass's max depth reflection to 7 and set the leaves max depth reflection to 1. Or am I missing something here?
z

[Neilg]

That doesnt work - the glass could have a max depth of 50, if a ray passes through it first it counts down the depth count of every object behind it. Your way is definately how I would expect control over reflection depths to work, but it doesnt.

See my second post here for an example - http://forums.chaosgroup.com/showthr...ight=max+depth
The glass depth stays the same, i'm only reducing the max depth on the white surface.

[Sbrusse]

Dynamic max depth bypassing refractions
Wish this could be true

[vlado]

Won't it be easier to fix the situations that cause the renderer to "grind to a halt" with lots of reflection/refraction bounces, rather than trying to do a hack of a hack? If you have any scenes like this I'd be very curious to look at them.

Best regards,
Vlado