Multi-region rendering

[TheLooopCGI]

Just a thought - how difficult would it be to implement a possibility of multi-region rendering into VFB? Meaning you could select more than just one region for renderer to process?

It would be much more convenient to select a few parts of the picture to re-render than select one region, render, select another region, render, select third region, render...

Thanks!
D.

[prateekvishwa]

i think that will be gr8!

[Morbid Angel]

I remember a script a long time ago which let you draw splines around areas you wanted to render...it could be what you want.

[TheLooopCGI]

That would be awesome.

I can't find the script though. Tried to google it but found nothing...

[Neilg]

You could also do this by selecting the objects you want to render, doing a crt-I to invert selection then go to vray properties and select matte object on and alpha to -1. That'll render only the initial objects you had selected.
I have a macro to do this on my quad menu so it's quick as you like.

[TheLooopCGI]

Yea but what about the surrounding objects? When I change a blue t-shirt for a red one, I'd still like to see the guy's neck in the render...

[Neilg]

If you need the neck, select the neck...

[TheLooopCGI]

I'm sorry, I realize what you're trying to do but it's really not helping. Hiding everything except the few objects you're interested in isn't really a substitution for a region render. Besides, in this way your whole picture is re-rendered so you lose everything else you rendered and have to do a comp later. It's more convenient to just render region by region...

By the way, shouldn't hiding the objects only to camera do the same thing as making them matte? Actually I think hiding them to camera should be more accurate because making the surrounding objects matte will probably change the light that's influencing the objects you're interested in.

Aaaanyway, could we have a response on the multi-region thingie from the developers, please?

[Neilg]

I didnt say for you to hide anything?
you've missed what I said to do. Only the objects you originally selected will show up in the render (and be rendered - the buckets will skip over everything else entirely as if it's rendering an empty scene), it comes with an alpha, and your objects still act like they are part of the scene - correct GI, reflection, refraction ec. It is exactly what you're after, except even more efficient because it only renders to the borders of what you need.

[TheLooopCGI]

By making the objects matte you're effectively hiding them.

How does your workflow help me if I want to do this:
1. Render a large scene with buildings and 3 people scattered around the picture with blue t-shirt.
2. Save the render as city with blue t-shirt guys and mark as done.
2. Exchange the blue t-shirts for red t-shirts.
3. Render the red t-shirts in regions so I still have the whole city in the frame buffer but only the t-shirts get changed.
4. Save the picture as city with red t-shirt guys.

If I do it your way and make everything except t-shirts matte I lose everything in the picture, no?

I really wonder who is the one who doesn't get the other one here...

[Neilg]

That was the point, yes - How does that help you if you need to change something the next day, or even a few hours later? Save the matte objects and lay them over in post.

Loosing everything else is the point, then you have a layer which is just shirts and can colour correct it separately in ps/fusion/whatever and only affect that object.

[TheLooopCGI]

It was only an example.

What if I'm not interested in the blue t-shirts at all and want only the red? What if it was a mistake? In your way I have to do the post and correct the mistake there. With region render you don't need to do this.

[TheLooopCGI]

Or what if I want to change a ring on the guy's finger? People are usually one whole object. I can't really select only the ring and finger so I get the whole picture rendered again.

I can see scenarios where your workflow is useful but you certainly can't use it generally like regions.

[TheLooopCGI]

By the way, like I said earlier - I strongly advise NOT turning the objects into mattes. The mattes affect the light in your scene differently than regular objects.

[Neilg]

By the way, like I said earlier - I strongly advise NOT turning the objects into mattes. The mattes affect the light in your scene differently than regular objects.

In what way? I've never experienced this and i'm sure it's not supposed to.